Exploration

The scope of exploration is wide. It covers your perception the world, your movement through it, and your ability to meet the non-social, non-combat challenges you face as you adventure. Few rules are as vital to the success of adventurers than those pertaining to vision, lighting, movement, and the environments you explore.

On this page: Light and Vision | Movement | Labyrinth Environments | Wilderness Environments | Urban Environments

Light and Vision

Vision is affected by four levels of illumination:

In an area of bright light, all characters can see clearly. Some creatures, such as those with light sensitivity and light blindness, take penalties while in areas of bright light. A creature can't use Stealth in an area of bright light unless it is invisible or has cover. Areas of bright light include outside in direct sunshine and inside the area of a daylight spell.

Normal light functions just like bright light, but characters with light sensitivity and light blindness do not take penalties. Areas of normal light include underneath a forest canopy during the day, within 20 feet of a torch, and inside the area of a light spell.

In an area of dim light, a character can see somewhat. Creatures within this area have concealment (20% miss chance in combat) from those without darkvision or the ability to see in darkness. A creature within an area of dim light can make a Stealth check to conceal itself. Areas of dim light include outside at night with a moon in the sky, bright starlight, and the area between 20 and 40 feet from a torch.

In areas of darkness, creatures without darkvision are effectively blinded. In addition to the obvious effects, a blinded creature has a 50% miss chance in combat (all opponents have total concealment), loses any Dexterity bonus to AC, takes a -2 penalty to AC, and takes a -4 penalty on Spot and Search checks that rely on sight and most Strength- and Dexterity-based skill checks. Areas of darkness include an unlit labyrinth chamber, most caverns, and outside on a cloudy, moonless night.

See Table: Light Sources and Illumination for the radius that a light source illuminates and how long it lasts.

Table: Light Sources and Illumination

Object	Normal Light	Dim Light	Duration
Candle	n/a1	0-5 ft.	1 hr.
Everburning torch	0-20 ft.	20-40 ft.	Permanent
Lamp, common	0-15 ft.	0-30 ft.	6 hr./pint
Lantern, bullseye	0-60-ft. cone	60-120-ft. cone	6 hr./pint
Lantern, hooded	0-30 ft.	30-60 ft.	6 hr./pint
Sunrod	0-30 ft.	30-60 ft.	6 hr.
Torch	0-20 ft.	20-40 ft.	1 hr.
Spell	Normal Light	Dim Light	Duration
Continual flame	0-20 ft.	20-40 ft.	Permanent
Dancing lights (torches)	0-20 ft. (each)	20-40 ft. (each)	1 min.
Daylight	0-60 ft.2	60-120 ft.	30 min.
Light	0-20 ft.	20-40 ft.	10 min.
1 A candle does not provide normal illumination, only dim illumination.
2 The light for a daylight spell is bright light.

These forms of vision interact with different levels of illumination:

• Normal Vision: You have sight that is the same as that of a healthy human.
• Low-Light Vision: You retain the ability to distinguish color and detail (including reading) in starlight, moonlight, torchlight, and similar conditions of poor illumination, that is, in "dim" lighting. Your miss chance due to concealment under dim conditions is only 5%, not 20%. Characters with low-light vision can see outdoors on a moonlit night as well as they can during the day. Check out the full rules for low-light vision.
• Darkvision is the extraordinary ability to see with no light source at all, out to a range specified for the creature. Darkvision is black-and-white only (colors cannot be discerned). It does not allow characters to see anything that they could not see otherwise; invisible objects are still invisible, and illusions are still visible as what they seem to be. Check out the full rules for darkvision.

Movement

There are three movement scales, as follows:

• Tactical, for combat, measured in feet (or 5-foot squares) per round.
• Local, for exploring an area, measured in feet per minute.
• Overland, for getting from place to place, measured in miles per hour or miles per day.

Modes of Movement: While moving at the different movement scales, creatures generally walk, hustle, or run.

Walk: A walk represents unhurried but purposeful movement (3 miles per hour for an unencumbered adult human).

Hustle: A hustle is a jog (about 6 miles per hour for an unencumbered human). A character moving his speed twice in a single round, or moving that speed in the same round that he or she performs a standard action or another move action, is hustling when he or she moves.

Run (×3): Moving three times speed is a running pace for a character in heavy armor (about 7 miles per hour for a human in full plate).

Run (×4): Moving four times speed is a running pace for a character in light, medium, or no armor ( about 12 miles per hour for an unencumbered human, or 9 miles per hour for a human in chainmail) See Table: Movement and Distance for details.

Table: Movement and Distance

Speed	15 feet	20 feet	30 feet	40 feet
One Round (Tactical)*
Walk	15 ft.	20 ft.	30 ft.	40 ft.
Hustle	30 ft.	40 ft.	60 ft.	80 ft.
Run (×3)	45 ft.	60 ft.	90 ft.	120 ft.
Run (×4)	60 ft.	80 ft.	120 ft.	160 ft.
One Minute (Local)
Walk	150 ft.	200 ft.	300 ft.	400 ft.
Hustle	300 ft.	400 ft.	600 ft.	800 ft.
Run (×3)	450 ft.	600 ft.	900 ft.	1,200 ft.
Run (×4)	600 ft.	800 ft.	1,200 ft.	1,600 ft.
One Hour (Overland)
Walk	1-1/2 miles	2 miles	3 miles	4 miles
Hustle	3 miles	4 miles	6 miles	8 miles
Run	—	—	—	—
One Day (Overland)
Walk	12 miles	16 miles	24 miles	32 miles
Hustle	—	—	—	—
Run	—	—	—	—
* Tactical movement is often measured in squares on the battle grid (1 square = 5 feet) rather than feet.

Tactical Movement

Tactical movement is used for combat. Characters generally don't walk during combat, for obvious reasons—they hustle or run instead. A character who moves his speed and takes some action is hustling for about half the round and doing something else the other half.

Table: Hampered Movement

Condition	Additional Movement Cost
Difficult terrain	×2
Obstacle*	×2
Poor visibility	×2
Impassable	—
* May require a skill check

Hampered Movement: Difficult terrain, obstacles, and poor visibility can hamper movement (see Table: Hampered Movement for details). When movement is hampered, each square moved into usually counts as two squares, effectively reducing the distance that a character can cover in a move.

If more than one hampering condition applies, multiply all additional costs that apply. This is a specific exception to the normal rule for doubling.

In some situations, your movement may be so hampered that you don't have sufficient speed even to move 5 feet (1 square). In such a case, you may use a full-round action to move 5 feet (1 square) in any direction, even diagonally. Even though this looks like a 5-foot step, it's not, and thus it provokes attacks of opportunity normally. (You can't take advantage of this rule to move through impassable terrain or to move when all movement is prohibited to you.)

You can't run or charge through any square that would hamper your movement.

Local Movement

Characters exploring an area use local movement, measured in feet per minute.

Walk: A character can walk without a problem on the local scale.

Hustle: A character can hustle without a problem on the local scale. See Overland Movement, below, for movement measured in miles per hour.

Run: A character can run for a number of rounds equal to his Constitution score on the local scale without needing to rest. See Combat for rules covering extended periods of running.

Table: Terrain and Overland Movement

Terrain	Highway	Road or Trail	Trackless
Desert, sandy	×1	×1/2	×1/2
Forest	×1	×1	×1/2
Hills	×1	×3/4	×1/2
Jungle	×1	×3/4	×1/4
Moor	×1	×1	×3/4
Mountains	×3/4	×3/4	×1/2
Plains	×1	×1	×3/4
Swamp	×1	×3/4	×1/2
Tundra, frozen	×1	×3/4	×3/4

Overland Movement

Characters covering long distances cross-country use overland movement. Overland movement is measured in miles per hour or miles per day. A day represents 8 hours of actual travel time. For rowed watercraft, a day represents 10 hours of rowing. For a sailing ship, it represents 24 hours.

Walk: A character can walk 8 hours in a day of travel without a problem. Walking for longer than that can wear him out (see Forced March, below).

Hustle: A character can hustle for 1 hour without a problem. Hustling for a second hour in between sleep cycles deals 1 point of nonlethal damage, and each additional hour deals twice the damage taken during the previous hour of hustling. A character who takes any nonlethal damage from hustling becomes fatigued.

A fatigued character can't run or charge and takes a penalty of -2 to Strength and Dexterity. Eliminating the nonlethal damage also eliminates the fatigue.

Run: A character can't run for an extended period of time. Attempts to run and rest in cycles effectively work out to a hustle.

Terrain: The terrain through which a character travels affects the distance he can cover in an hour or a day (see Table: Terrain and Overland Movement). A highway is a straight, major, paved road. A road is typically a dirt track. A trail is like a road, except that it allows only single-file travel and does not benefit a party traveling with vehicles. Trackless terrain is a wild area with no paths.

Forced March: In a day of normal walking, a character walks for eight hours. The rest of the daylight time is spent making and breaking camp, resting, and eating.

A character can walk for more than eight hours in a day by making a forced march. For each hour of marching beyond eight hours, a Constitution check (DC 10, +2 per extra hour) is required. If the check fails, the character takes 1d6 points of nonlethal damage. A character who takes any nonlethal damage from a forced march becomes fatigued. Eliminating the nonlethal damage also eliminates the fatigue. It's possible for a character to march into unconsciousness by pushing himself too hard.

Mounted Movement: A mount bearing a rider can move at a hustle. The damage it takes when doing so, however, is lethal damage, not nonlethal damage. The creature can also be ridden in a forced march, but its Constitution checks automatically fail, and the damage it takes is lethal damage. Mounts also become fatigued when they take any damage from hustling or forced marches.

See Table: Mounts and Vehicles: Mounts and Vehicles for mounted speeds and speeds for vehicles pulled by draft animals.

Waterborne Movement: See Table: Mounts and Vehicles: Mounts and Vehicles for speeds for water vehicles.

Table: Mounts and Vehicles

Mount/Vehicle	Per Hour	Per Day
Mount (carrying load)
Light horse	6 miles	48 miles
Light horse (175–525 lbs.)1	4 miles	32 miles
Heavy horse	5 miles	40 miles
Heavy horse (229–690 lbs.)1	3-1/2 miles	28 miles
Pony	4 miles	32 miles
Pony (151–450 lbs.)1	3 miles	24 miles
Dog, riding	4 miles	32 miles
Dog, riding (101–300 lbs.)1	3 miles	24 miles
Cart or wagon	2 miles	16 miles
Ship
Raft or barge (poled or towed)2	1/2 mile	5 miles
Keelboat (rowed)2	1 mile	10 miles
Rowboat (rowed)2	1-1/2 miles	15 miles
Sailing ship (sailed)	2 miles	48 miles
Warship (sailed and rowed)	2-1/2 miles	60 miles
Longship (sailed and rowed)	3 miles	72 miles
Galley (rowed and sailed)	4 miles	96 miles
1 Quadrupeds, such as horses, can carry heavier loads than characters can. See Carrying Capacity for more information.
2 Rafts, barges, keelboats, and rowboats are most often used on lakes and rivers. If going downstream, add the speed of the current (typically 3 miles per hour) to the speed of the vehicle. In addition to 10 hours of being rowed, the vehicle can also float an additional 14 hours, if someone can guide it, adding an additional 42 miles to the daily distance traveled. These vehicles can’t be rowed against any significant current, but they can be pulled upstream by draft animals on the shores.

Evasion and Pursuit

In round-by-round movement, when simply counting off squares, it's impossible for a slow character to get away from a determined fast character without mitigating circumstances. Likewise, it's no problem for a fast character to get away from a slower one.

When the speeds of the two concerned characters are equal, there's a simple way to resolve a chase: If one creature is pursuing another, both are moving at the same speed, and the chase continues for at least a few rounds, have them make opposed Dexterity checks to see who is the faster over those rounds. If the creature being chased wins, it escapes. If the pursuer wins, it catches the fleeing creature.

Sometimes a chase occurs overland and could last all day, with the two sides only occasionally getting glimpses of each other at a distance. In the case of a long chase, an opposed Constitution check made by all parties determines which can keep pace the longest. If the creature being chased rolls the highest, it gets away. If not, the chaser runs down its prey, outlasting it with stamina.

Labyrinths

Of all the strange places that an adventurer might explore, none is deadlier than the labyrinth. These labyrinths, full of deadly traps, hungry monsters, and priceless treasure, test every skill a character possesses. These rules can apply to labyrinths of any type, from the wreck of a sunken ship to a vast cave complex.

Types of Labyrinths

The four basic labyrinth types are defined by their current status. Many labyrinths are variations on these basic types or combinations of more than one of them. Sometimes old labyrinths are used again and again by different inhabitants for different purposes.

Ruined Structure: Once occupied, this place is now abandoned (completely or in part) by its original creator or creators, and other creatures have wandered in. Many subterranean creatures look for abandoned underground constructions in which to make their lairs. Any traps that might exist have probably been set off, but wandering beasts might very well be common.

Occupied Structure: This type of labyrinth is still in use. Creatures (usually intelligent) live there, although they might not be the labyrinth's creators. An occupied structure might be a home, a fortress, a temple, an active mine, a prison, or a headquarters. This type of labyrinth is less likely to have traps or wandering beasts, and more likely to have organized guards—both on watch and on patrol. Traps or wandering beasts that might be encountered are usually under the control of the occupants. Occupied structures have furnishings to suit the inhabitants, as well as decorations, supplies, and the ability for occupants to move around. The inhabitants might have a communication system, and they almost certainly control an exit to the outside.

Some labyrinths are partially occupied and partially empty or in ruins. In such cases, the occupants are typically not the original builders, but instead a group of intelligent creatures that have set up their base, lair, or fortification within an abandoned labyrinth.

Safe Storage: When people want to protect something, they sometimes bury it underground. Whether the item they want to protect is a fabulous treasure, a forbidden artifact, or the dead body of an important figure, these valuable objects are placed within a labyrinth and surrounded by barriers, traps, and guardians.

The safe storage labyrinth is the most likely to have traps but the least likely to have wandering beasts. This type of labyrinth is normally built for function rather than appearance, but sometimes it has ornamentation in the form of statuary or painted walls. This is particularly true of the tombs of important people.

Sometimes, however, a vault or a crypt is constructed in such a way as to house living guardians. The problem with this strategy is that something must be done to keep the creatures alive between intrusion attempts. Magic is usually the best solution to provide food and water for these creatures. Builders of vaults or tombs often use undead creatures or constructs, both of which have no need for sustenance or rest, to guard their labyrinths. Magic traps can attack intruders by summoning monsters into the labyrinth that disappear when their task is done.

Natural Cavern Complex: Underground caves provide homes for all sorts of subterranean monsters. Created naturally and connected by labyrinthine tunnel systems, these caverns lack any sort of pattern, order, or decoration. With no intelligent force behind its construction, this type of labyrinth is the least likely to have traps or even doors.

Fungi of all sorts thrive in caves, sometimes growing in huge forests of mushrooms and puffballs. Subterranean predators prowl these forests, looking for weaker creatures feeding upon the fungi. Some varieties of fungus give off a phosphorescent glow, providing a natural cavern complex with its own limited light source. In other areas, a daylight spell or similar magical effect can provide enough light for green plants to grow.

Natural cavern complexes often connect with other types of labyrinths, the caves having been discovered when the manufactured labyrinths were delved. A cavern complex can connect two otherwise unrelated labyrinths, sometimes creating a strange mixed environment. A natural cavern complex joined with another labyrinth often provides a route by which subterranean creatures find their way into a manufactured labyrinth and populate it.

Walls

Masonry walls—stones piled on top of each other, usually but not always held in place with mortar—often divide labyrinths into corridors and chambers. Labyrinth walls can also be hewn from solid rock, leaving them with a rough, chiseled look. Still other labyrinth walls can be the smooth, unblemished stone of a naturally occurring cave. Labyrinth walls are difficult to break down or through, but they're generally easy to climb.

Table: Walls

Wall Type	Typical Thickness	Break DC	Hardness	Hit Points1	Climb DC
Masonry	1 ft.	35	8	90 hp	20
Superior masonry	1 ft.	35	8	90 hp	25
Reinforced masonry	1 ft.	45	8	180 hp	20
Hewn stone	3 ft.	50	8	540 hp	25
Unworked stone	5 ft.	65	8	900 hp	15
Iron	3 in.	30	10	90 hp	25
Paper	Paper-thin	1	—	1 hp	30
Wooden	6 in.	20	5	60 hp	21
Magically treated2	—	+20	×2	×23	—
1 Per 10-foot-by-10-foot section.
2 This modifier can be applied to any of the other wall types.
3 Or an additional 50 hit points, whichever is greater.

Masonry Walls: The most common kind of labyrinth wall, masonry walls are usually at least 1 foot thick. Often, these ancient walls sport cracks and crevices, and sometimes dangerous slimes or small monsters live in these areas and wait for prey. Masonry walls stop all but the loudest noises. It takes a DC 20 Climb check to travel along a masonry wall.

Superior Masonry Walls: Sometimes masonry walls are better built (smoother, with tighter-fitting stones and less cracking), and occasionally these superior walls are covered with plaster or stucco. Covered walls often bear paintings, carved reliefs, or other decoration. Superior masonry walls are no more difficult to destroy than regular masonry walls but are more difficult to climb (DC 25).

Reinforced Masonry Walls: These are masonry walls with iron bars on one or both sides of the wall, or placed within the wall to strengthen it. The hardness of a reinforced wall remains the same, but its hit points are doubled and the Strength check DC to break through it is increased by 10.

Hewn Stone Walls: Such walls usually result when a chamber or passage is tunneled out from solid rock. The rough surface of a hewn wall frequently provides minuscule ledges where fungus grows and fissures where vermin, bats, and subterranean snakes live. When such a wall has an “other side” (meaning it separates two chambers in the labyrinth), the wall is usually at least 3 feet thick; anything thinner risks collapsing from the weight of all the stone overhead. It takes a DC 25 Climb check to climb a hewn stone wall.

Unworked Stone Walls: These surfaces are uneven and rarely flat. They are smooth to the touch but filled with tiny holes, hidden alcoves, and ledges at various heights. They're also usually wet or at least damp, since it's water that most frequently creates natural caves. When such a wall has an “other side,” the wall is usually at least 5 feet thick. It takes a DC 15 Climb check to move along an unworked stone wall.

Iron Walls: These walls are placed within labyrinths around important places, such as vaults.

Paper Walls: Paper walls are placed as screens to block line of sight, but nothing more.

Wooden Walls: Wooden walls often exist as recent additions to older labyrinths, used to create animal pens, storage bins, and temporary structures, or just to make a number of smaller rooms out of a larger one.

Magically Treated Walls: These walls are stronger than average, with a greater hardness, more hit points, and a higher break DC. Magic can usually double the hardness and hit points of a wall and add up to 20 to the break DC. A magically treated wall also gains a saving throw against spells that could affect it, with the save bonus equaling 2 + 1/2 the caster level of the magic reinforcing the wall. Creating a magic wall requires the Craft Wondrous Item feat and the expenditure of 1,500 gp for each 10-foot-by-10-foot wall section.

Walls with Arrow Slits: Walls with arrow slits can be made of any durable material but are most commonly masonry, hewn stone, or wood. Such a wall allows defenders to fire arrows or crossbow bolts at intruders from behind the safety of the wall. Archers behind arrow slits have improved cover that gives them a +8 bonus to AC, a +4 bonus on Reflex saves, and the benefits of the improved evasion class feature.

Floors

As with walls, labyrinth floors come in many types.

Flagstone: Like masonry walls, flagstone floors are made of fitted stones. They are usually cracked and only somewhat level. Slime and mold grows in the cracks. Sometimes water runs in rivulets between the stones or sits in stagnant puddles. Flagstone is the most common labyrinth floor.

Uneven Flagstone: Over time, some floors can become so uneven that a DC 10 Acrobatics check is required to run or charge across the surface. Failure means the character can't move that round. Floors as treacherous as this should be the exception, not the rule.

Hewn Stone Floors: Rough and uneven, hewn floors are usually covered with loose stones, gravel, dirt, or other debris. A DC 10 Acrobatics check is required to run or charge across such a floor. Failure means the character can still act, but can't run or charge in this round.

Light Rubble: Small chunks of debris litter the ground. Light rubble adds 2 to the DC of Acrobatics checks.

Dense Rubble: The ground is covered with debris of all sizes. It costs 2 squares of movement to enter a square with dense rubble. Dense rubble adds 5 to the DC of Acrobatics checks, and it adds 2 to the DC of Stealth checks.

Smooth Stone Floors: Finished and sometimes even polished, smooth floors are found only in labyrinths made by capable and careful builders.

Natural Stone Floors: The floor of a natural cave is as uneven as the walls. Caves rarely have flat surfaces of any great size. Rather, their floors have many levels. Some adjacent floor surfaces might vary in elevation by only a foot, so that moving from one to the other is no more difficult than negotiating a stair step, but in other places the floor might suddenly drop off or rise up several feet or more, requiring Climb checks to get from one surface to the other. Unless a path has been worn and well marked in the floor of a natural cave, it takes 2 squares of movement to enter a square with a natural stone floor, and the DC of Acrobatics checks increases by 5. Running and charging are impossible, except along paths.

Slippery: Water, ice, slime, or blood can make any of the labyrinth floors described in this section more treacherous. Slippery floors increase the DC of Acrobatics checks by 5.

Grate: A grate often covers a pit or an area lower than the main floor. Grates are usually made from iron, but large ones can also be made from iron-bound timbers. Many grates have hinges to allow access to what lies below (such grates can be locked like any door), while others are permanent and designed to not move. A typical 1-inch-thick iron grate has 25 hit points, hardness 10, and a DC of 27 for Strength checks to break through it or tear it loose.

Ledge: Ledges allow creatures to walk above some lower area. They often circle around pits, run along underground streams, form balconies around large rooms, or provide a place for archers to stand while firing upon enemies below. Narrow ledges (12 inches wide or less) require those moving along them to make Acrobatics checks. Failure results in the moving character falling off the ledge. Ledges sometimes have railings along the wall. In such a case, characters gain a +5 circumstance bonus on Acrobatics checks to move along the ledge. A character who is next to a railing gains a +2 circumstance bonus on his opposed Strength check to avoid being bull rushed off the edge.

Ledges can also have low walls 2 to 3 feet high along their edges. Such walls provide cover against attackers within 30 feet on the other side of the wall, as long as the target is closer to the low wall than the attacker is.

Transparent Floor: Transparent floors, made of reinforced glass or magic materials (even a wall of force), allow a dangerous setting to be viewed safely from above. Transparent floors are sometimes placed over lava pools, arenas, monster dens, and torture chambers. They can be used by defenders to watch key areas for intruders.

Sliding Floors: A sliding floor is a type of trap door, designed to be moved and thus reveal something that lies beneath it. A typical sliding floor moves so slowly that anyone standing on one can avoid falling into the gap it creates, assuming there's somewhere else to go. If such a floor slides quickly enough that there's a chance of a character falling into whatever lies beneath—a spiked pit, a vat of burning oil, or a pool filled with sharks—then it's a trap.

Trap Floors: Some floors are designed to become suddenly dangerous. With the application of just the right amount of weight, or the pull of a lever somewhere nearby, spikes protrude from the floor, gouts of steam or flame shoot up from hidden holes, or the entire floor tilts. These strange floors are sometimes found in arenas, designed to make combats more exciting and deadly. Construct these floors as you would any other trap.

Doors

Doors in labyrinths are much more than mere entrances and exits. Often they can be encounters all by themselves. Labyrinth doors come in three basic types: wooden, stone, and iron.

Table: Doors

Door Type	Typical Thickness	Hardness	Hit Points	Break DC
				Stuck	Locked
Simple wooden	1 in.	5	10 hp	13	15
Good wooden	1-1/2 in.	5	15 hp	16	18
Strong wooden	2 in.	5	20 hp	23	25
Stone	4 in.	8	60 hp	28	28
Iron	2 in.	10	60 hp	28	28
Portcullis, wooden	3 in	5	30 hp	25*	25*
Portcullis, iron	2 in.	10	60 hp	25*	25*
Lock	—	15	30 hp	—	—
Hinge	—	10	30 hp	—	—
* DC to lift. Use appropriate door figure for breaking.

Wooden Doors: Constructed of thick planks nailed together, sometimes bound with iron for strength (and to reduce swelling from labyrinth dampness), wooden doors are the most common type. Wooden doors come in varying strengths: simple, good, and strong. Simple doors (break DC 15) are not meant to keep out motivated attackers. Good doors (break DC 18), while sturdy and long-lasting, are still not meant to take much punishment. Strong doors (break DC 25) are bound in iron and are a sturdy barrier to those attempting to get past them. Iron hinges fasten the door to its frame, and typically a circular pull-ring in the center is there to help open it. Sometimes, instead of a pull-ring, a door has an iron pull-bar on one or both sides of the door to serve as a handle. In inhabited labyrinths, these doors are usually well-maintained (not stuck) and unlocked, although important areas are locked up if possible.

Stone: Carved from solid blocks of stone, these heavy, unwieldy doors are often built so that they pivot when opened, although dwarves and other skilled craftsfolk are able to fashion hinges strong enough to hold up a stone door. Secret doors concealed within a stone wall are usually stone doors. Otherwise, such doors stand as tough barriers protecting something important beyond. Thus, they are often locked or barred.

Iron: Rusted but sturdy, iron doors in a labyrinth are hinged like wooden doors. These doors are the toughest form of nonmagical door. They are usually locked or barred.

Breaking Doors: Labyrinth doors might be locked, trapped, reinforced, barred, magically sealed, or sometimes just stuck. All but the weakest characters can eventually knock down a door with a heavy tool such as a sledgehammer, and a number of spells and magic items give characters an easy way around a locked door.

Attempts to literally chop down a door with a slashing or bludgeoning weapon use the hardness and hit points given in Table: Doors. When assigning a DC to an attempt to knock a door down, use the following as guidelines.

DC 10 or Lower: a door just about anyone can break open.

DC 11–15: a door that a strong person could break with one try and an average person might be able to break with one try.

DC 16–20: a door that almost anyone could break, given time.

DC 21–25: a door that only a strong or very strong person has a hope of breaking, probably not on the first try.

DC 26 or Higher: a door that only an exceptionally strong person has a hope of breaking.

Locks: Labyrinth doors are often locked, and thus the Disable Device skill comes in very handy. Locks are usually built into the door, either on the edge opposite the hinges or right in the middle of the door. Built-in locks either control an iron bar that juts out of the door and into the wall of its frame, or else a sliding iron bar or heavy wooden bar that rests behind the entire door. By contrast, padlocks are not built-in but usually run through two rings, one on the door and the other on the wall. More complex locks, such as combination locks and puzzle locks, are usually built into the door itself. Because such keyless locks are larger and more complex, they are typically only found in sturdy doors (strong wooden, stone, or iron doors).

The Disable Device DC to pick a lock often falls within the range of 20 to 30, although locks with lower or higher DCs can exist. A door can have more than one lock, each of which must be unlocked separately. Locks are often trapped, usually with poison needles that extend out to prick a rogue's finger.

Breaking a lock is sometimes quicker than breaking the whole door. If a PC wants to whack at a lock with a weapon, treat the typical lock as having hardness 15 and 30 hit points. A lock can only be broken if it can be attacked separately from the door, which means that a built-in lock is immune to this sort of treatment. In an occupied labyrinth, every locked door should have a key somewhere.

A special door might have a lock with no key, instead requiring that the right combination of nearby levers must be manipulated or the right symbols must be pressed on a keypad in the correct sequence to open the door.

Stuck Doors: Labyrinths are often damp, and sometimes doors get stuck, particularly wooden doors. Assume that about 10% of wooden doors and 5% of non-wooden doors are stuck. These numbers can be doubled (to 20% and 10%, respectively) for long-abandoned or neglected labyrinths.

Barred Doors: When characters try to bash down a barred door, it's the quality of the bar that matters, not the material the door is made of. It takes a DC 25 Strength check to break through a door with a wooden bar, and a DC 30 Strength check if the bar is made of iron. Characters can attack the door and destroy it instead, leaving the bar hanging in the now-open doorway.

Magic Seals: Spells such as arcane lock can discourage passage through a door. A door with an arcane lock spell on it is considered locked even if it doesn't have a physical lock. It takes a knock spell, a dispel magic spell, or a successful Strength check to open such a door.

Hinges: Most doors have hinges, but sliding doors do not. They usually have tracks or grooves instead, allowing them to slide easily to one side.

Standard Hinges: These hinges are metal, joining one edge of the door to the door frame or wall. Remember that the door swings open toward the side with the hinges. (So, if the hinges are on the PCs' side, the door opens toward them; otherwise it opens away from them.) Adventurers can take the hinges apart one at a time with successful Disable Device checks (assuming the hinges are on their side of the door, of course). Such a task has a DC of 20 because most hinges are rusted or stuck. Breaking a hinge is difficult. Most have hardness 10 and 30 hit points. The break DC for a hinge is the same as for breaking down the door.

Nested Hinges: These hinges are much more complex than ordinary hinges, and are found only in areas of excellent construction. These hinges are built into the wall and allow the door to swing open in either direction. PCs can't get at the hinges to fool with them unless they break through the door frame or wall. Nested hinges are typically found on stone doors but sometimes on wooden or iron doors as well.

Pivots: Pivots aren't really hinges at all, but simple knobs jutting from the top and bottom of the door that fit into holes in the door frame, allowing the door to spin. The advantages of pivots are that they can't be dismantled like hinges and they're simple to make. The disadvantage is that since the door pivots on its center of gravity (typically in the middle), nothing larger than half the door's width can fit through without squeezing. Doors with pivots are usually stone and often quite wide to overcome this disadvantage. Another solution is to place the pivot toward one side and have the door be thicker at that end and thinner toward the other end so that it opens more like a normal door. Secret doors in walls often turn on pivots, since the lack of hinges makes it easier to hide the door's presence. Pivots also allow objects such as bookcases to be used as secret doors.

Secret Doors: Disguised as a bare patch of wall (or floor or ceiling), a bookcase, a fireplace, or a fountain, a secret door leads to a secret passage or room. Someone examining the area finds a secret door, if one exists, on a successful Spot or Search check (DC 20 for a typical secret door to DC 30 for a well-hidden secret door).

Many secret doors require special methods of opening, such as hidden buttons or pressure plates. Secret doors can open like normal doors, or they might pivot, slide, sink, rise, or even lower like a drawbridge to permit access. Builders might put a secret door low near the floor or high in a wall, making it difficult to find or reach. Wizards and sorcerers have a spell, phase door, that allows them to create a magic secret door that only they can use.

Magic Doors: Enchanted by the original builders, a door might speak to explorers, warning them away. It might be protected from harm, increasing its hardness or giving it more hit points as well as an improved saving throw bonus against disintegrate and similar spells. A magic door might not lead into the space behind it, but instead might be a portal to a faraway place or even another plane of existence. Other magic doors might require passwords or special keys to open them.

Portcullises: These special doors consist of iron or thick, ironbound wooden shafts that descend from recesses in the ceilings above archways. Sometimes a portcullis has crossbars that create a grid, sometimes not. Typically raised by means of a winch or a capstan, a portcullis can be dropped quickly, and the shafts end in spikes to discourage anyone from standing underneath (or from attempting to dive under it as it drops). Once it is dropped, a portcullis locks, unless it is so large that no normal person could lift it anyway. In any event, lifting a typical portcullis requires a DC 25 Strength check.

Walls, Doors, and Detect Spells -- Stone walls, iron walls, and iron doors are usually thick enough to block most detect spells, such as detect thoughts. Wooden walls, wooden doors, and stone doors are usually not thick enough to do so. A secret stone door built into a wall and as thick as the wall itself (at least 1 foot) does block most detect spells.

Stairs

Stairs are the most common means of traveling up and down within a labyrinth. A character can move up or down stairs as part of their movement without penalty, but they cannot run on them. Increase the DC of any Acrobatics skill check made on stairs by 4. Some stairs are particularly steep and are treated as difficult terrain.

Labyrinth Hazards

Cave-Ins and Collapses (CR 8)

Cave-ins and collapsing tunnels are extremely dangerous. Not only do labyrinth explorers face the danger of being crushed by tons of falling rock, but even if they survive they might be buried beneath a pile of rubble or cut off from the only known exit. A cave-in buries anyone in the middle of the collapsing area, and then sliding debris damages anyone in the periphery of the collapse. A typical corridor subject to a cave-in might have a bury zone with a 15-foot radius and a 10-foot-wide slide zone extending beyond the bury zone. A weakened ceiling can be spotted with a DC 20 Knowledge (engineering) or DC 20 Craft (stonemasonry) check. Remember that Craft checks can be made untrained as Intelligence checks. A dwarf can make such a check if he simply passes within 10 feet of a weakened ceiling.

A weakened ceiling might collapse when subjected to a major impact or concussion. A character can cause a cave-in by destroying half the pillars holding up the ceiling.

Characters in the bury zone of a cave-in take 8d6 points of damage, or half that amount if they make a DC 15 Reflex save. They are subsequently buried. Characters in the slide zone take 3d6 points of damage, or no damage at all if they make a DC 15 Reflex save. Characters in the slide zone who fail their saves are buried.

Characters take 1d6 points of nonlethal damage per minute while buried. If such a character falls unconscious, he must make a DC 15 Constitution check each minute. If it fails, he takes 1d6 points of lethal damage each minute until freed or dead.

Characters who aren't buried can dig out their friends. In 1 minute, using only her hands, a character can clear rocks and debris equal to five times her heavy load limit. The amount of loose stone that fills a 5-foot-by-5-foot area weighs 1 ton (2,000 pounds). Armed with an appropriate tool, such as a pick, crowbar, or shovel, a digger can clear loose stone twice as quickly as by hand. A buried character can attempt to free himself with a DC 25 Strength check.

Slimes, Molds, and Fungi

In a labyrinth's damp, dark recesses, molds and fungi thrive. For purposes of spells and other special effects, all slimes, molds, and fungi are treated as plants. Like traps, dangerous slimes and molds have CRs, and characters earn XP for encountering them.

A form of glistening organic sludge coats almost anything that remains in the damp and dark for too long. This kind of slime, though it might be repulsive, is not dangerous. Molds and fungi flourish in dark, cool, damp places. While some are as inoffensive as the normal labyrinth slime, others are quite dangerous. Mushrooms, puffballs, yeasts, mildew, and other sorts of bulbous, fibrous, or flat patches of fungi can be found throughout most labyrinths. They are usually inoffensive, and some are even edible (although most are unappealing or odd-tasting).

Brown Mold (CR 2): Brown mold feeds on warmth, drawing heat from anything around it. It normally comes in patches 5 feet in diameter, and the temperature is always cold in a 30-foot radius around it. Living creatures within 5 feet of it take 3d6 points of nonlethal cold damage. Fire brought within 5 feet of brown mold causes the mold to instantly double in size. Cold damage, such as from a cone of cold, instantly destroys it.

Green Slime (CR 4): This labyrinth peril is a dangerous variety of normal slime. Green slime devours flesh and organic materials on contact and is even capable of dissolving metal. Bright green, wet, and sticky, it clings to walls, floors, and ceilings in patches, reproducing as it consumes organic matter. It drops from walls and ceilings when it detects movement (and possible food) below.

A single 5-foot square of green slime deals 1d6 points of Constitution damage per round while it devours flesh. On the first round of contact, the slime can be scraped off a creature (destroying the scraping device), but after that it must be frozen, burned, or cut away (dealing damage to the victim as well). Anything that deals cold or fire damage, sunlight, or a remove disease spell destroys a patch of green slime. Against wood or metal, green slime deals 2d6 points of damage per round, ignoring metal's hardness but not that of wood. It does not harm stone.

Phosphorescent Fungus: This strange underground fungus gives off a soft violet glow that illuminates underground caverns and passages as well as a candle does. Rare patches of fungus illuminate as well as a torch does.

Shrieker: This human-sized purple mushroom emits a piercing sound that lasts for 1d3 rounds whenever there is movement or a light source within 10 feet. This shriek makes it impossible to hear any other sound within 50 feet. The sound attracts nearby creatures that are disposed to investigate it. Some creatures that live near shriekers learn that this noise means there is food or an intruder nearby.

Yellow Mold (CR 6): If disturbed, a 5-foot square of this mold bursts forth with a cloud of poisonous spores. All within 10 feet of the mold must make a DC 15 Fortitude save or take 1d3 points of Constitution damage. Another DC 15 Fortitude save is required once per round for the next 5 rounds, to avoid taking 1d3 points of Constitution damage each round. A successful Fortitude save ends this effect. Fire destroys yellow mold, and sunlight renders it dormant.

Wilderness

Outside the safety of city walls, the wilderness is a dangerous place, and many adventurers have gotten lost in its trackless wilds or fallen victim to deadly weather. The following rules give you guidelines on running adventures in a wilderness setting.

Forest Terrain

Forest terrain can be divided into three categories: sparse, medium, and dense. An immense forest could have all three categories within its borders, with more sparse terrain at the outer edge of the forest and dense forest at its heart.

The table below describes in general terms how likely it is that a given square has a terrain element in it.

	Category of Forest
	Sparse	Medium	Dense
Typical trees	50%	70%	80%
Massive trees	—	10%	20%
Light undergrowth	50%	70%	50%
Heavy undergrowth	—	20%	50%

Trees: The most important terrain element in a forest is the trees, obviously. A creature standing in the same square as a tree gains partial cover, which grants a +2 bonus to AC and a +1 bonus on Reflex saves. The presence of a tree doesn't otherwise affect a creature's fighting space, because it's assumed that the creature is using the tree to its advantage when it can. The trunk of a typical tree has AC 4, hardness 5, and 150 hp. A DC 15 Climb check is sufficient to climb a tree. Medium and dense forests have massive trees as well. These trees take up an entire square and provide cover to anyone behind them. They have AC 3, hardness 5, and 600 hp. Like their smaller counterparts, it takes a DC 15 Climb check to climb them.

Undergrowth: Vines, roots, and short bushes cover much of the ground in a forest. A space covered with light undergrowth costs 2 squares of movement to move into, and provides concealment. Undergrowth increases the DC of Acrobatics and Stealth checks by 2 because the leaves and branches get in the way. Heavy undergrowth costs 4 squares of movement to move into and provides concealment with a 30% miss chance (instead of the usual 20%). It increases the DC of Acrobatics checks by 5. Heavy undergrowth is easy to hide in, granting a +5 circumstance bonus on Stealth checks. Running and charging are impossible. Squares with undergrowth are often clustered together. Undergrowth and trees aren't mutually exclusive; it's common for a 5-foot square to have both a tree and undergrowth.

Forest Canopy: It's common for elves and other forest dwellers to live on raised platforms far above the surface floor. These wooden platforms often have rope bridges between them. To get to the treehouses, characters ascend the trees' branches (Climb DC 15), use rope ladders (Climb DC 0), or take pulley elevators (which can be made to rise a number of feet equal to a Strength check, made each round as a full-round action). Creatures on platforms or branches in a forest canopy are considered to have cover when fighting creatures on the ground, and in medium or dense forests they have concealment as well.

Other Forest Terrain Elements: Fallen logs generally stand about 3 feet high and provide cover just as low walls do. They cost 5 feet of movement to cross. Forest streams average 5 to 10 feet wide and no more than 5 feet deep. Pathways wind through most forests, allowing normal movement and providing neither cover nor concealment. These paths are less common in dense forests, but even unexplored forests have occasional game trails.

Stealth and Detection in a Forest: In a sparse forest, the maximum distance at which a Spot or Search check for detecting the nearby presence of others can succeed is 3d6 × 10 feet. In a medium forest, this distance is 2d8 × 10 feet, and in a dense forest it is 2d6 × 10 feet.

Because any square with undergrowth provides concealment, it's usually easy for a creature to use the Stealth skill in the forest. Logs and massive trees provide cover, which also makes hiding possible.

The background noise in the forest makes Spot or Search checks that rely on sound more difficult, increasing the DC of the check by 2 per 10 feet, not 1.

Forest Fires (CR 6)

Most campfire sparks ignite nothing, but if conditions are dry, winds are strong, or the forest floor is dried out and flammable, a forest fire can result. Lightning strikes often set trees ablaze and start forest fires in this way. Whatever the cause of the fire, travelers can get caught in the conflagration.

A forest fire can be spotted from as far away as 2d6 × 100 feet by a character who makes a Spot or Search check, treating the fire as a Colossal creature (reducing the DC by 16). If all characters fail their Spot or Search checks, the fire moves closer to them. They automatically see it when it closes to half the original distance. With proper elevation, the smoke from a forest fire can be spotted as far as 10 miles away.

Characters who are blinded or otherwise unable to make Spot or Search checks can feel the heat of the fire (and thus automatically “spot” it) when it is 100 feet away.

The leading edge of a fire (the downwind side) can advance faster than a human can run (assume 120 feet per round for winds of moderate strength). Once a particular portion of the forest is ablaze, it remains so for 2d4 × 10 minutes before dying to a smoking wasteland. Characters overtaken by a forest fire might find the leading edge of the fire advancing away from them faster than they can keep up, trapping them deeper and deeper within its grasp.

Within the bounds of a forest fire, a character faces three dangers: heat damage, catching on fire, and smoke inhalation.

Heat Damage: Getting caught within a forest fire is even worse than being exposed to extreme heat (see Heat Dangers). Breathing the air causes a character to take 1d6 points of fire damage per round (no save). In addition, a character must make a Fortitude save every 5 rounds (DC 15, +1 per previous check) or take 1d4 points of nonlethal damage. A character who holds his breath can avoid the lethal damage, but not the nonlethal damage. Those wearing heavy clothing or any sort of armor take a -4 penalty on their saving throws. Those wearing metal armor or who come into contact with very hot metal are affected as if by a heat metal spell.

Catching on Fire: Characters engulfed in a forest fire are at risk of catching on fire when the leading edge of the fire overtakes them, and continue to be at risk once per minute thereafter.

Smoke Inhalation: Forest fires naturally produce a great deal of smoke. A character who breathes heavy smoke must make a Fortitude save each round (DC 15, +1 per previous check) or spend that round choking and coughing. A character who chokes for 2 consecutive rounds takes 1d6 points of nonlethal damage. Smoke also provides concealment to characters within it.

Marsh Terrain

Two categories of marsh exist: relatively dry moors and watery swamps. Both are often bordered by lakes (described in Aquatic Terrain), which are effectively a third category of terrain found in marshes.

	Marsh Category
	Moor	Swamp
Shallow bog	20%	40%
Deep bog	5%	20%
Light undergrowth	30%	20%
Heavy undergrowth	10%	20%

Bogs: If a square is part of a shallow bog, it has deep mud or standing water of about 1 foot in depth. It costs 2 squares of movement to move into a square with a shallow bog, and the DC of Acrobatics checks in such a square increases by 2.

A square that is part of a deep bog has roughly 4 feet of standing water. It costs Medium or larger creatures 4 squares of movement to move into a square with a deep bog, or characters can swim if they wish. Small or smaller creatures must swim to move through a deep bog. Tumbling is impossible in a deep bog.

The water in a deep bog provides cover for Medium or larger creatures. Smaller creatures gain improved cover (+8 bonus to AC, +4 bonus on Reflex saves). Medium or larger creatures can crouch as a move action to gain this improved cover. Creatures with this improved cover take a -10 penalty on attacks against creatures that aren't underwater.

Deep bog squares are usually clustered together and surrounded by an irregular ring of shallow bog squares.

Both shallow and deep bogs increase the DC of Stealth checks by 2.

Undergrowth: The bushes, rushes, and other tall grasses in marshes function as undergrowth does in a forest. A square that is part of a bog does not also have undergrowth.

Hedgerows: Common in moors, hedgerows are tangles of stones, soil, and thorny bushes. Narrow hedgerows function as low walls, and it takes 3 squares of movement to cross them. Wide hedgerows are more than 5 feet tall and take up entire squares. They provide total cover, just as a wall does. It takes 4 squares of movement to move through a square with a wide hedgerow; creatures that succeed on a DC 10 Climb check need only 2 squares of movement to move through the square.

Other Marsh Terrain Elements: Some marshes, particularly swamps, have trees just as forests do, usually clustered in small stands. Paths lead across many marshes, winding to avoid bog areas. As in forests, paths allow normal movement and don't provide the concealment that undergrowth does.

Stealth and Detection in a Marsh: In a marsh, the maximum distance at which a Spot or Search check for detecting the nearby presence of others can succeed is 6d6 × 10 feet. In a swamp, this distance is 2d8 × 10 feet.

Undergrowth and deep bogs provide plentiful concealment, so it's easy to use Stealth in a marsh.

Quicksand (CR 4)

Patches of quicksand present a deceptively solid appearance (appearing as undergrowth or open land) that might trap careless characters. A character approaching a patch of quicksand at a normal pace is entitled to a DC 8 Survival check to spot the danger before stepping in, but charging or running characters don't have a chance to detect a hidden patch before blundering into it. A typical patch of quicksand is 20 feet in diameter; the momentum of a charging or running character carries him 1d2 × 5 feet into the quicksand.

Effects of Quicksand: Characters in quicksand must make a DC 10 Swim check every round to simply tread water in place, or a DC 15 Swim check to move 5 feet in whatever direction is desired. If a trapped character fails this check by 5 or more, he sinks below the surface and begins to drown whenever he can no longer hold his breath (see the Swim skill description in Using Skills).

Characters below the surface of quicksand may swim back to the surface with a successful Swim check (DC 15, +1 per consecutive round of being under the surface).

Rescue: Pulling out a character trapped in quicksand can be difficult. A rescuer needs a branch, spear haft, rope, or similar tool that enables him to reach the victim with one end of it. Then he must make a DC 15 Strength check to successfully pull the victim, and the victim must make a DC 10 Strength check to hold onto the branch, pole, or rope. If both checks succeed, the victim is pulled 5 feet closer to safety. If the victim fails to hold on, he must make a DC 15 Swim check immediately to stay above the surface.

Hills Terrain

A hill can exist in most other types of terrain, but hills can also dominate the landscape. Hills terrain is divided into two categories: gentle hills and rugged hills. Hills terrain often serves as a transition zone between rugged terrain such as mountains and flat terrain such as plains.

	Hills Category
	Gentle Hills	Rugged Hills
Gradual slope	75%	40%
Steep slope	20%	50%
Cliff	5%	10%
Light undergrowth	15%	15%

Gradual Slope: This incline isn't steep enough to affect movement, but characters gain a +1 bonus on melee attacks against foes downhill from them.

Steep Slope: Characters moving uphill (to an adjacent square of higher elevation) must spend 2 squares of movement to enter each square of steep slope. Characters running or charging downhill (moving to an adjacent square of lower elevation) must succeed on a DC 10 Acrobatics check upon entering the first steep slope square. Mounted characters make a DC 10 Ride check instead. Characters who fail this check stumble and must end their movement 1d2 × 5 feet later. Characters who fail by 5 or more fall prone in the square where they end their movement. A steep slope increases the DC of Acrobatics checks by 2.

Cliff: A cliff typically requires a DC 15 Climb check to scale and is 1d4 × 10 feet tall, although the needs of your map might mandate a taller cliff. A cliff isn't perfectly vertical, taking up 5-foot squares if it's less than 30 feet tall and 10-foot squares if it's 30 feet or taller.

Light Undergrowth: Sagebrush and other scrubby bushes grow on hills, although they rarely cover the landscape. Light undergrowth provides concealment and increases the DC of Acrobatics and Stealth checks by 2.

Other Hills Terrain Elements: Trees aren't out of place in hills terrain, and valleys often have active streams (5 to 10 feet wide and no more than 5 feet deep) or dry streambeds (treat as a trench 5 to 10 feet across) in them. If you add a stream or streambed, remember that water always flows downhill.

Stealth and Detection in Hills: In gentle hills, the maximum distance at which a Spot or Search check for detecting the nearby presence of others can succeed is 2d10 × 10 feet. In rugged hills, this distance is 2d6 × 10 feet.

Hiding in hills terrain can be difficult if there isn't undergrowth around. A hilltop or ridge provides enough cover to hide from anyone below the hilltop or ridge.

Mountain Terrain

The three mountain terrain categories are alpine meadows, rugged mountains, and forbidding mountains. As characters ascend into a mountainous area, they're likely to face each terrain category in turn, beginning with alpine meadows, extending through rugged mountains, and reaching forbidding mountains near the summit.

Mountains have an important terrain element, the rock wall, that is marked on the border between squares rather than taking up squares itself.

	Mountain Category
	Alpine Meadow	Rugged	Forbidding
Gradual slope	50%	25%	15%
Steep slope	40%	55%	55%
Cliff	10%	15%	20%
Chasm	—	5%	10%
Light undergrowth	20%	10%	—
Scree	—	20%	30%
Dense rubble	—	20%	30%

Gradual and Steep Slopes: These function as described in Hills Terrain.

Cliff: These terrain elements also function like their hills terrain counterparts, but they're typically 2d6 × 10 feet tall. Cliffs taller than 80 feet take up 20 feet of horizontal space.

Chasm: Usually formed by natural geological processes, chasms function like pits in a labyrinth setting. Chasms aren't hidden, so characters won't fall into them by accident (although bull rushes are another story). A typical chasm is 2d4 × 10 feet deep, at least 20 feet long, and anywhere from 5 feet to 20 feet wide. It takes a DC 15 Climb check to climb out of a chasm. In forbidding mountain terrain, chasms are typically 2d8 × 10 feet deep.

Light Undergrowth: This functions as described in Forest Terrain.

Scree: A field of shifting gravel, scree doesn't affect speed, but it can be treacherous on a slope. The DC of Acrobatics checks increases by 2 if there's scree on a gradual slope and by 5 if there's scree on a steep slope. The DC of Stealth checks increases by 2 if the scree is on a slope of any kind.

Dense Rubble: The ground is covered with rocks of all sizes. It costs 2 squares of movement to enter a square with dense rubble. The DC of Acrobatics checks on dense rubble increases by 5, and the DC of Stealth checks increases by 2.

Rock Wall: A vertical plane of stone, rock walls require DC 25 Climb checks to ascend. A typical rock wall is 2d4 × 10 feet tall in rugged mountains and 2d8 × 10 feet tall in forbidding mountains. Rock walls are drawn on the edges of squares, not in the squares themselves.

Cave Entrance: Found in cliff and steep slope squares and next to rock walls, cave entrances are typically between 5 and 20 feet wide and 5 feet deep. A cave could be anything from a simple chamber to the entrance to an elaborate labyrinth. Caves used as monster lairs typically have 1d3 rooms that are 1d4 × 10 feet across.

Other Mountain Terrain Features: Most alpine meadows begin above the treeline, so trees and other forest elements are rare in the mountains. Mountain terrain can include active streams (5 to 10 feet wide and no more than 5 feet deep) and dry streambeds (treat as a trench 5 to 10 feet across). Particularly high-altitude areas tend to be colder than the lowland areas that surround them, so they might be covered in ice sheets (described in Desert Terrain).

Stealth and Detection in Mountains: As a guideline, the maximum distance in mountain terrain at which a Spot or Search check for detecting the nearby presence of others can succeed is 4d10 × 10 feet. Certain peaks and ridgelines afford much better vantage points, of course, and twisting valleys and canyons have much shorter spotting distances. Because there's little vegetation to obstruct line of sight, the specifics on your map are your best guide for the range at which an encounter could begin. As in hills terrain, a ridge or peak provides enough cover to hide from anyone below the high point.

It's easier to hear faraway sounds in the mountains. The DC of Spot or Search checks that rely on sound increase by 1 per 20 feet between listener and source, not per 10 feet.

Avalanches (CR 7)

The combination of high peaks and heavy snowfalls means that avalanches are a deadly peril in many mountainous areas. While avalanches of snow and ice are common, it's also possible to have an avalanche of rock and soil.

An avalanche can be spotted from as far away as 1d10 × 500 feet by a character who makes a DC 20 Spot or Search check, treating the avalanche as a Colossal creature. If all characters fail their Spot or Search checks to determine the encounter distance, the avalanche moves closer to them, and they automatically become aware of it when it closes to half the original distance. It's possible to hear an avalanche coming even if you can't see it. Under optimum conditions (no other loud noises occurring), a character who makes a DC 15 Spot or Search check can hear the avalanche or landslide when it is 1d6 × 500 feet away. This check might have a DC of 20, 25, or higher in conditions where hearing is difficult (such as in the middle of a thunderstorm).

A landslide or avalanche consists of two distinct areas: the bury zone (in the direct path of the falling debris) and the slide zone (the area the debris spreads out to encompass). Characters in the bury zone always take damage from the avalanche; characters in the slide zone might be able to get out of the way. Characters in the bury zone take 8d6 points of damage, or half that amount if they make a DC 15 Reflex save. They are subsequently buried. Characters in the slide zone take 3d6 points of damage, or no damage if they make a DC 15 Reflex save. Those who fail their saves are buried.

Buried characters take 1d6 points of nonlethal damage per minute. If a buried character falls unconscious, he must make a DC 15 Constitution check or take 1d6 points of lethal damage each minute thereafter until freed or dead.

The typical avalanche has a width of 1d6 × 100 feet, from one edge of the slide zone to the opposite edge. The bury zone in the center of the avalanche is half as wide as the avalanche's full width.

To determine the precise location of characters in the path of an avalanche, roll 1d6 × 20; the result is the number of feet from the center of the path taken by the bury zone to the center of the party's location. Avalanches of snow and ice advance at a speed of 500 feet per round, while rock and soil avalanches travel at a speed of 250 feet per round.

Mountain Travel

High altitude travel can be extremely fatiguing—and sometimes deadly—to creatures that aren't used to it. Cold becomes extreme, and the lack of oxygen in the air can wear down even the most hardy of warriors.

Acclimated Characters: Creatures accustomed to high altitude generally fare better than lowlanders. Any creature with an Environment entry that includes mountains is considered native to the area and acclimated to the high altitude. Characters can also acclimate themselves by living at high altitude for a month. Characters who spend more than two months away from the mountains must reacclimate themselves when they return. Undead, constructs, and other creatures that do not breathe are immune to altitude effects.

Altitude Zones: In general, mountains present three possible altitude bands: low pass, low peak/high pass, and high peak.

Low Pass (lower than 5,000 feet): Most travel in low mountains takes place in low passes, a zone consisting largely of alpine meadows and forests. Travelers might find the going difficult (which is reflected in the movement modifiers for traveling through mountains), but the altitude itself has no game effect.

Low Peak or High Pass (5,000 to 15,000 feet): Ascending to the highest slopes of low mountains, or most normal travel through high mountains, falls into this category. All non-acclimated creatures labor to breathe in the thin air at this altitude. Characters must succeed on a Fortitude save each hour (DC 15, +1 per previous check) or be fatigued. The fatigue ends when the character descends to an altitude with more air. Acclimated characters do not have to attempt the Fortitude save.

High Peak (more than 15,000 feet): The highest mountains exceed 15,000 feet in height. At these elevations, creatures are subject to both high altitude fatigue (as described above) and altitude sickness, whether or not they're acclimated to high altitudes. Altitude sickness represents long-term oxygen deprivation, and affects mental and physical ability scores. After each 6-hour period a character spends at an altitude of over 15,000 feet, he must succeed on a Fortitude save (DC 15, +1 per previous check) or take 1 point of damage to all ability scores. Creatures acclimated to high altitude receive a +4 competence bonus on their saving throws to resist high altitude effects and altitude sickness, but eventually even seasoned mountaineers must abandon these dangerous elevations.

Desert Terrain

Desert terrain exists in warm, temperate, and cold climates, but all deserts share one common trait: little rain. The three categories of desert terrain are tundra (cold desert), rocky deserts (often temperate), and sandy deserts (often warm).

Tundra differs from the other desert categories in two important ways. Because snow and ice cover much of the landscape, it's easy to find water. During the height of summer, the permafrost thaws to a depth of a foot or so, turning the landscape into a vast field of mud. The muddy tundra affects movement and skill use as the shallow bogs described in Marsh Terrain, although there's little standing water.

The table below describes terrain elements found in each of the three desert categories. The terrain elements on this table are mutually exclusive; for instance, a square of tundra might contain either light undergrowth or an ice sheet, but not both.

	Desert Category
	Tundra	Rocky	Sandy
Light undergrowth	15%	5%	5%
Ice sheet	25%	—	—
Light rubble	5%	30%	10%
Dense rubble	—	30%	5%
Sand dunes	—	—	50%

Light Undergrowth: Consisting of scrubby, hardy bushes and cacti, light undergrowth functions as described for other terrain types.

Ice Sheet: The ground is covered with slippery ice. It costs 2 squares of movement to enter a square covered by an ice sheet, and the DC of Acrobatics checks there increases by 5. A DC 10 Acrobatics check is required to run or charge across an ice sheet.

Light Rubble: Small rocks are strewn across the ground, making nimble movement more difficult. The DC of Acrobatics checks increases by 2.

Dense Rubble: This terrain feature consists of more and larger stones. It costs 2 squares of movement to enter a square with dense rubble. The DC of Acrobatics checks increases by 5, and the DC of Stealth checks increases by 2.

Sand Dunes: Created by the action of wind on sand, dunes function as hills that move. If the wind is strong and consistent, a sand dune can move several hundred feet in a week's time. Sand dunes can cover hundreds of squares. They always have a gentle slope pointing in the direction of the prevailing wind and a steep slope on the leeward side.

Other Desert Terrain Features: Tundra is sometimes bordered by forests, and the occasional tree isn't out of place in the cold wastes. Rocky deserts have towers and mesas consisting of flat ground surrounded on all sides by cliffs and steep slopes (as described in Mountain Terrain). Sandy deserts sometimes have quicksand; this functions as described in Marsh Terrain, although desert quicksand is a waterless mixture of fine sand and dust. All desert terrain is crisscrossed with dry streambeds (treat as trenches 5 to 15 feet wide) that fill with water on the rare occasions when rain falls.

Stealth and Detection in the Desert: In general, the maximum distance in desert terrain at which a Spot or Search check for detecting the nearby presence of others can succeed is 6d6 × 20 feet; beyond this distance, elevation changes and heat distortion in warm deserts makes sight-based Spot or Search impossible. The presence of dunes in sandy deserts limits spotting distance to 6d6 × 10 feet. The scarcity of undergrowth or other elements that offer concealment or cover makes using Stealth more difficult.

Sandstorms (CR 2)

A sandstorm reduces visibility to 1d10 × 5 feet and provides a -4 penalty on Spot or Search checks. A sandstorm deals 1d3 points of nonlethal damage per hour to any creatures caught in the open, and leaves a thin coating of sand in its wake. Driving sand creeps in through all but the most secure seals and seams, chafing skin and contaminating carried gear.

Plains Terrain

Plains come in three categories: farms, grasslands, and battlefields. Farms are common in settled areas, while grasslands represent untamed plains. The battlefields where large armies clash are temporary places, usually reclaimed by natural vegetation or the farmer's plow. Battlefields represent a third terrain category because adventurers tend to spend a lot of time there, not because they're particularly prevalent.

The table below shows the proportions of terrain elements in the different categories of plains. On a farm, light undergrowth represents most mature grain crops, so farms growing vegetable crops will have less light undergrowth, as will all farms during the time between harvest and a few months after planting.

The terrain elements in the table below are mutually exclusive.

	Plains Category
	Farm	Grassland	Battlefield
Light undergrowth	40%	20%	10%
Heavy undergrowth	—	10%	—
Light rubble	—	—	10%
Trench	5%	—	5%
Berm	—	—	5%

Undergrowth: Whether they're crops or natural vegetation, the tall grasses of the plains function like light undergrowth in a forest. Particularly thick bushes form patches of heavy undergrowth that dot the landscape in grasslands.

Light Rubble: On the battlefield, light rubble usually represents something that was destroyed: the ruins of a building or the scattered remnants of a stone wall, for example. It functions as described in the Desert Terrain section.

Trench: Often dug before a battle to protect soldiers, a trench functions as a low wall, except that it provides no cover against adjacent foes. It costs 2 squares of movement to leave a trench, but it costs nothing extra to enter one. Creatures outside a trench who make a melee attack against a creature inside the trench gain a +1 bonus on melee attacks because they have higher ground. In farm terrain, trenches are generally irrigation ditches.

Berm: A common defensive structure, a berm is a low, earthen wall that slows movement and provides a measure of cover. Put a berm on the map by drawing two adjacent rows of steep slope (described in Hills Terrain), with the edges of the berm on the downhill side. Thus, a character crossing a 2-square berm will travel uphill for 1 square, then downhill for 1 square. Two square berms provide cover as low walls for anyone standing behind them. Larger berms provide the low wall benefit for anyone standing 1 square downhill from the top of the berm.

Fences: Wooden fences are generally used to contain livestock or impede oncoming soldiers. It costs an extra square of movement to cross a wooden fence. A stone fence provides a measure of cover as well, functioning as low walls. Mounted characters can cross a fence without slowing their movement if they succeed on a DC 15 Ride check. If the check fails, the steed crosses the fence, but the rider falls out of the saddle.

Other Plains Terrain Features: Occasional trees dot the landscape in many plains, although on battlefields they're often felled to provide raw material for siege engines (described in Urban Features). Hedgerows (described in Marsh Terrain) are found in plains as well. Streams, generally 5 to 20 feet wide and 5 to 10 feet deep, are commonplace.

Stealth and Detection in Plains: In plains terrain, the maximum distance at which a Spot or Search check for detecting the nearby presence of others can succeed is 6d6 × 40 feet, although the specifics of your map might restrict line of sight. Cover and concealment are not uncommon, so a good place of refuge is often nearby, if not right at hand.

Aquatic Terrain

Aquatic terrain is the least hospitable to most PCs, because they can't breathe there. Aquatic terrain doesn't offer the variety that land terrain does. The ocean floor holds many marvels, including undersea analogues of any of the terrain elements described earlier in this section, but if characters find themselves in the water because they were bull rushed off the deck of a pirate ship, the tall kelp beds hundreds of feet below them don't matter. Accordingly, these rules simply divide aquatic terrain into two categories: flowing water (such as streams and rivers) and non-flowing water (such as lakes and oceans).

Flowing Water: Large, placid rivers move at only a few miles per hour, so they function as still water for most purposes. But some rivers and streams are swifter; anything floating in them moves downstream at a speed of 10 to 40 feet per round. The fastest rapids send swimmers bobbing downstream at 60 to 90 feet per round. Fast rivers are always at least rough water (Swim DC 15), and whitewater rapids are stormy water (Swim DC 20). If a character is in moving water, move her downstream the indicated distance at the end of her turn. A character trying to maintain her position relative to the riverbank can spend some or all of her turn swimming upstream.

Swept Away: Characters swept away by a river moving 60 feet per round or faster must make DC 20 Swim checks every round to avoid going under. If a character gets a check result of 5 or more over the minimum necessary, she arrests her motion by catching a rock, tree limb, or bottom snag—she is no longer being carried along by the flow of the water. Escaping the rapids by reaching the bank requires three DC 20 Swim checks in a row. Characters arrested by a rock, limb, or snag can't escape under their own power unless they strike out into the water and attempt to swim their way clear. Other characters can rescue them as if they were trapped in quicksand (described in Marsh Terrain).

Non-Flowing Water: Lakes and oceans simply require a swim speed or successful Swim checks to move through (DC 10 in calm water, DC 15 in rough water, DC 20 in stormy water). Characters need a way to breathe if they're underwater; failing that, they risk drowning. When underwater, characters can move in any direction.

Stealth and Detection Underwater: How far you can see underwater depends on the water's clarity. As a guideline, creatures can see 4d8 × 10 feet if the water is clear, and 1d8 × 10 feet if it's murky. Moving water is always murky, unless it's in a particularly large, slow-moving river.

It's hard to find cover or concealment to hide underwater (except along the sea floor).

Invisibility: An invisible creature displaces water and leaves a visible, body-shaped “bubble” where the water was displaced. The creature still has concealment (20% miss chance), but not total concealment (50% miss chance).

Underwater Combat

Land-based creatures can have considerable difficulty when fighting in water. Water affects a creature's attack rolls, damage, and movement. In some cases a creature's opponents might get a bonus on attacks. The effects are summarized on Table: Combat Adjustments Underwater. They apply whenever a character is swimming, walking in chest-deep water, or walking along the bottom of a body of water.

Table: Combat Adjustments Underwater

Condition	Attack/Damage		Movement	Off Balance?1
	Slashing or Bludgeoning	Piercing
Freedom of movement	normal/normal	normal/normal	normal	No
Has a swim speed	-2/half	normal	normal	No
Successful Swim check	-2/half2	normal	quarter or half3	No
Firm footing4	-2/half2	normal	half	No
None of the above	-2/half2	-2/half	normal	Yes
1 Creatures flailing about in the water (usually because they failed their Swim checks) have a hard time fighting effectively. An off-balance creature loses its Dexterity bonus to Armor Class, and opponents gain a +2 bonus on attacks against it.
2 A creature without freedom of movement effects or a swim speed makes grapple checks underwater at a -2 penalty, but deals damage normally when grappling.
3 A successful Swim check lets a creature move one-quarter its speed as a move action or one-half its speed as a full-round action.
4 Creatures have firm footing when walking along the bottom, braced against a ship's hull, or the like. A creature can only walk along the bottom if it wears or carries enough gear to weigh itself down: at least 16 pounds for Medium creatures, twice that for each size category larger than Medium, and half that for each size category smaller than Medium.

Ranged Attacks Underwater: Thrown weapons are ineffective underwater, even when launched from land. Attacks with other ranged weapons take a -2 penalty on attack rolls for every 5 feet of water they pass through, in addition to the normal penalties for range.

Attacks from Land: Characters swimming, floating, or treading water on the surface, or wading in water at least chest deep, have improved cover (+8 bonus to AC, +4 bonus on Reflex saves) from opponents on land. Land-bound opponents who have freedom of movement effects ignore this cover when making melee attacks against targets in the water. A completely submerged creature has total cover against opponents on land unless those opponents have freedom of movement effects. Magical effects are unaffected except for those that require attack rolls (which are treated like any other effects) and fire effects.

Fire: Nonmagical fire (including alchemist's fire) does not burn underwater. Spells or spell-like effects with the fire descriptor are ineffective underwater unless the caster makes a caster level check (DC 20 + spell level). If the check succeeds, the spell creates a bubble of steam instead of its usual fiery effect, but otherwise the spell works as described. A supernatural fire effect is ineffective underwater unless its description states otherwise. The surface of a body of water blocks line of effect for any fire spell. If the caster has made the caster level check to make the fire spell usable underwater, the surface still blocks the spell's line of effect.

Spellcasting Underwater: Casting spells while submerged can be difficult for those who cannot breathe underwater. A creature that cannot breathe water must make a concentration check (DC 15 + spell level) to cast a spell underwater (this is in addition to the caster level check to successfully cast a fire spell underwater). Creatures that can breathe water are unaffected and can cast spells normally. Some spells might function differently underwater, subject to GM discretion.

Floods

In many wilderness areas, river floods are a common occurrence.

In spring, an enormous snowmelt can engorge the streams and rivers it feeds. Other catastrophic events such as massive rainstorms or the destruction of a dam can create floods as well.

During a flood, rivers become wider, deeper, and swifter. Assume that a river rises by 1d10+10 feet during the spring flood, and its width increases by a factor of 1d4 × 50%. Fords might disappear for days, bridges might be swept away, and even ferries might not be able to manage the crossing of a flooded river. A river in flood makes Swim checks one category harder (calm water becomes rough, and rough water becomes stormy). Rivers also become 50% swifter.

Urban Environments

At first glance, a city is much like a labyrinth, made up of walls, doors, rooms, and corridors. Adventures that take place in cities have two salient differences from their labyrinth counterparts, however. Characters have greater access to resources, and they must contend with law enforcement.

Access to Resources: Unlike in labyrinths and the wilderness, characters can buy and sell gear quickly in a city. A large city or metropolis probably has high-level NPCs and experts in obscure fields of knowledge who can provide assistance and decipher clues. And when the PCs are battered and bruised, they can retreat to the comfort of a room at an inn.

The freedom to retreat and ready access to the marketplace means that the players have a greater degree of control over the pacing of an urban adventure.

Law Enforcement: The other key distinctions between adventuring in a city and delving into a labyrinth is that a labyrinth is, almost by definition, a lawless place where the only law is that of the jungle: kill or be killed. A city, on the other hand, is held together by a code of laws, many of which are explicitly designed to prevent the sort of killing and looting that adventurers engage in all the time. Even so, most cities' laws recognize monsters as a threat to the stability the city relies on, and prohibitions about murder rarely apply to monsters such as aberrations or evil outsiders. Most evil humanoids, however, are typically protected by the same laws that protect all the citizens of the city. Having an evil alignment is not a crime (except in some severely theocratic cities, perhaps, with the magical power to back up the law); only evil deeds are against the law. Even when adventurers encounter an evildoer in the act of perpetrating some heinous evil upon the populace of the city, the law tends to frown on the sort of vigilante justice that leaves the evildoer dead or otherwise unable to testify at a trial.

Weapon and Spell Restrictions

Different cities have different laws about such issues as carrying weapons in public and restricting spellcasters.

The city's laws might not affect all characters equally. A monk isn't hampered at all by a law about peace-bonding weapons, but a cleric is reduced to a fraction of his power if all holy symbols are confiscated at the city's gates.

Walls and Gates

Many cities are surrounded by walls. A typical small city wall is a fortified stone wall 5 feet thick and 20 feet high. Such a wall is fairly smooth, requiring a DC 30 Climb check to scale. The walls are crenellated on one side to provide a low wall for the guards atop it, and there is just barely room for guards to walk along the top of the wall. A typical small city wall has AC 3, hardness 8, and 450 hp per 10-foot section.

A typical large city wall is 10 feet thick and 30 feet high, with crenellations on both sides for the guards on top of the wall. It is likewise smooth, requiring a DC 30 Climb check to scale. Such a wall has AC 3, hardness 8, and 720 hp per 10-foot section.

A typical metropolis wall is 15 feet thick and 40 feet tall. It has crenellations on both sides and often has a tunnel and small rooms running through its interior. Metropolis walls have AC 3, hardness 8, and 1,170 hp per 10-foot section.

Unlike smaller cities, metropolises often have interior walls as well as surrounding walls—either old walls that the city has outgrown, or walls dividing individual districts from each other. Sometimes these walls are as large and thick as the outer walls, but more often they have the characteristics of a large city's or small city's walls.

Watchtowers: Some city walls are adorned with watchtowers set at irregular intervals. Few cities have enough guards to keep someone constantly stationed at every tower, unless the city is expecting attack from outside. The towers provide a superior view of the surrounding countryside as well as a point of defense against invaders.

Watchtowers are typically 10 feet higher than the wall they adjoin, and their diameter is 5 times the thickness of the wall. Arrow slits line the outer sides of the upper stories of a tower, and the top is crenellated like the surrounding walls are. In a small tower (25 feet in diameter adjoining a 5-foot-thick wall), a simple ladder typically connects the tower's stories and its roof. In a larger tower, stairs serve that purpose.

Heavy wooden doors, reinforced with iron and bearing good locks (Disable Device DC 30), block entry to a tower, unless the tower is in regular use. As a rule, the captain of the guard keeps the keys to the towers secured on her person, and second copies are in the city's inner fortress or barracks.

Gates: A typical city gate is a gatehouse with two portcullises and murder holes above the space between them. In towns and some small cities, the primary entry is through iron double doors set into the city wall.

Gates are usually open during the day and locked or barred at night. Usually, one gate lets in travelers after sunset and is staffed by guards who will open it for someone who seems honest, presents proper papers, or offers a large enough bribe (depending on the city and the guards).

Guards and Soldiers

A city typically has full-time military personnel equal to 1% of its adult population, in addition to militia or conscript soldiers equal to 5% of the population. The full-time soldiers are city guards responsible for maintaining order within the city, similar to the role of modern police, and (to a lesser extent) for defending the city from outside assault. Conscript soldiers are called up to serve in case of an attack on the city.

A typical city guard force works on three 8-hour shifts, with 30% of the force on a day shift (8 a.m. to 4 p.m.), 35% on an evening shift (4 p.m. to 12 a.m.), and 35% on a night shift (12 a.m. to 8 a.m.). At any given time, 80% of the guards on duty are on the streets patrolling, while the remaining 20% are stationed at various posts throughout the city where they can respond to nearby alarms. At least one such guard post is present within each neighborhood of a city (each neighborhood consisting of several districts).

The majority of a city guard force is made up of warriors, mostly 1st level. Officers include higher-level warriors, fighters, a fair number of clerics, and wizards or sorcerers, as well as multiclass fighter/spellcasters.

Siege Engines

Siege engines are large weapons, temporary structures, or pieces of equipment traditionally used in besieging castles or fortresses.

Table: Siege Engines

Item	Cost	Damage	Critical Range	Increment	Typical Crew
Catapult, heavy	800 gp	6d6	—	200 ft. (100 ft. minimum)	4
Catapult, light	550 gp	4d6	—	150 ft. (100 ft. minimum)	2
Ballista	500 gp	3d8	19–20	120 ft.	1
Ram	1,000 gp	3d6*	—	—	10
Siege tower	2,000 gp	—	—	—	20
* See description for special rules.

Catapult Attack Modifiers

Condition	Modifier
No line of sight to target square	-6
Successive shots (crew can see where most recent misses landed)	Cumulative +2 per previous miss (maximum +10)
Successive shots (crew can't see where most recent misses landed, but observer is providing feedback)	Cumulative +1 per previous miss (maximum +5)

Siege engines are treated as difficult devices if someone tries to disable them using Disable Device. This takes 2d4 rounds and requires a DC 20 Disable Device check. Siege engines are typically made out of wood and have an AC of 3 (-5 Dex, -2 size), a Hardness of 5, and 80 hit points. Siege engines made up of a different material might have different values. Some siege engines are armored as well. Treat the siege engine as a Huge creature to determine the cost of such armor. Siege engines can be crafted as masterwork and enchanted as magic weapons, adding bonuses on attack rolls to the checks made to hit with the siege engine. A masterwork siege engine costs 300 gp more than the listed price. Enchanting a siege engine costs twice the normal amount. For example, a +1 flaming heavy catapult, armored with full plate, would have an AC of 11 and would cost 23,100 gp (800 gp base + 6,000 gp for the armor + 300 gp masterwork + 16,000 gp for the enhancements).

Catapult, Heavy: A heavy catapult is a massive engine capable of throwing rocks or heavy objects with great force. Because the catapult throws its payload in a high arc, it can hit squares out of its line of sight. To fire a heavy catapult, the crew chief makes a special check against DC 15 using only his base attack bonus, Intelligence modifier, range increment penalty, and the appropriate modifiers from the lower section of Table: Siege Engines. If the check succeeds, the catapult stone hits the square the catapult was aimed at, dealing the indicated damage to any object or character in the square. Characters who succeed on a DC 15 Reflex save take half damage. Once a catapult stone hits a square, subsequent shots hit the same square unless the catapult is reaimed or the wind changes direction or speed.

If a catapult stone misses, roll 1d8 to determine where it lands. This determines the misdirection of the throw, with 1 being back toward the catapult and 2 through 8 counting clockwise around the target square. Finally, count 1d4 squares away from the target square for every range increment of the attack.

Loading a catapult requires a series of full-round actions. It takes a DC 15 Strength check to winch the throwing arm down; most catapults have wheels to allow up to two crew members to use the aid another action, assisting the main winch operator. A DC 15 Profession (siege engineer) check latches the arm into place, and then another DC 15 Profession (siege engineer) check loads the catapult ammunition. It takes four full-round actions to reaim a heavy catapult (multiple crew members can perform these full-round actions in the same round, so it would take a crew of four only 1 round to reaim the catapult).

A heavy catapult takes up a space 15 feet across.

Catapult, Light: This is a smaller, lighter version of the heavy catapult. It functions as the heavy catapult, except that it takes a DC 10 Strength check to winch the arm into place, and only two full-round actions are required to reaim the catapult.

A light catapult takes up a space 10 feet across.

Ballista: A ballista is essentially a Huge heavy crossbow fixed in place. Its size makes it hard for most creatures to aim it. Thus, a Medium creature takes a -4 penalty on attack rolls when using a ballista, and a Small creature takes a -6 penalty. It takes a creature smaller than Large two full-round actions to reload the ballista after firing.

A ballista takes up a space 5 feet across.

Ram: This heavy pole is sometimes suspended from a movable scaffold that allows the crew to swing it back and forth against objects. As a full-round action, the character closest to the front of the ram makes an attack roll against the AC of the construction, applying the -4 penalty for lack of proficiency. It's not possible to be proficient with this device. In addition to the damage given on Table: Siege Engines, up to nine other characters holding the ram can add their Strength modifiers to the ram's damage, if they devote an attack action to doing so. It takes at least one Huge or larger creature, two Large creatures, four Medium creatures, or eight Small creatures to swing a ram.

A ram is typically 30 feet long. In a battle, the creatures wielding the ram stand in two adjacent columns of equal length, with the ram between them.

Siege Tower: This device is a massive wooden tower on wheels or rollers that can be rolled up against a wall to allow attackers to scale the tower and thus get to the top of the wall with cover. The wooden walls are usually 1 foot thick.

A typical siege tower takes up a space 15 feet across. The creatures inside push it at a base land speed of 10 feet (and a siege tower can't run). The eight creatures pushing on the ground floor have total cover, and those on higher floors get improved cover and can fire through arrow slits.

City Streets

Typical city streets are narrow and twisting. Most streets average 15 to 20 feet wide, while alleys range from 10 feet wide to only 5 feet. Cobblestones in good condition allow normal movement, but roads in poor repair and heavily rutted dirt streets are considered light rubble, increasing the DC of Acrobatics checks by 2.

Some cities have no larger thoroughfares, particularly cities that gradually grew from small settlements to larger cities. Cities that are planned, or perhaps have suffered a major fire that allowed authorities to construct new roads through formerly inhabited areas, might have a few larger streets through town. These main roads are 25 feet wide—offering room for wagons to pass each other—with 5-foot-wide sidewalks on either side.

Crowds: Urban streets are often full of people going about their daily lives. In most cases, it isn't necessary to put every 1st-level commoner on the map when a fight breaks out on the city's main thoroughfare. Instead, just indicate which squares on the map contain crowds. If crowds see something obviously dangerous, they'll move away at 30 feet per round at initiative count 0. It takes 2 squares of movement to enter a square with crowds. The crowds provide cover for anyone who does so, enabling a Stealth check and providing a bonus to Armor Class and on Reflex saves.

Directing Crowds: It takes a DC 15 Diplomacy check or DC 20 Intimidate check to convince a crowd to move in a particular direction, and the crowd must be able to hear or see the character making the attempt. It takes a full-round action to make the Diplomacy check, but only a free action to make the Intimidate check.

If two or more characters are trying to direct a crowd in different directions, they make opposed Diplomacy or Intimidate checks to determine to whom the crowd listens. The crowd ignores everyone if none of the characters' check results beat the DCs given above.

Above and Beneath the Streets

Rooftops: Getting to a roof usually requires climbing a wall, unless the character can reach a roof by jumping down from a higher window, balcony, or bridge. Flat roofs, common only in warm climates (as accumulated snow can cause a flat roof to collapse), are easy to run across. Moving along the peak of a pitched roof requires a DC 20 Acrobatics check. Moving on an angled roof surface without changing altitude (moving parallel to the peak, in other words) requires a DC 15 Acrobatics check. Moving up and down across the peak of a roof requires a DC 10 Acrobatics check.

Eventually a character runs out of roof, requiring a long jump across to the next roof or down to the ground. The distance to the closest roof is usually 1d3 × 5 feet horizontally, but the next roof is equally likely to be 5 feet higher, 5 feet lower, or the same height. Use the guidelines in the Acrobatics skill (a horizontal jump's peak height is one-fourth of the horizontal distance) to determine whether a character can make a jump.

Sewers: To get into the sewers, most characters open a grate (a full-round action) and jump down 10 feet. Sewers are built exactly like labyrinths, except that they're much more likely to have floors that are slippery or covered with water. Sewers are also similar to labyrinths in terms of creatures liable to be encountered therein. Some cities were built atop the ruins of older civilizations, so their sewers sometimes lead to treasures and dangers from a bygone age.

City Buildings

Most city buildings fall into three categories. The majority of buildings in the city are two to five stories high, built side-by-side to form long rows separated by secondary or main streets. These row houses usually have businesses on the ground floor, with offices or apartments above.

Inns, successful businesses, and large warehouses—as well as millers, tanners, and other businesses that require extra space—are generally large, free-standing buildings with up to five stories.

Finally, small residences, shops, warehouses, or storage sheds are simple, one-story wooden buildings, especially if they're in poorer neighborhoods.

Most city buildings are made of a combination of stone or clay brick (on the lower one or two stories) and timbers (for the upper stories, interior walls, and floors). Roofs are a mixture of boards, thatch, and slates, sealed with pitch. A typical lower-story wall is 1 foot thick, with AC 3, hardness 8, 90 hp, and a Climb DC of 25. Upper-story walls are 6 inches thick, with AC 3, hardness 5, 60 hp, and a Climb DC of 21. Exterior doors on most buildings are good wooden doors that are usually kept locked, except on public buildings such as shops and taverns.

City Lights

If a city has main thoroughfares, they are lined with lanterns hanging at a height of 7 feet from building awnings. These lanterns are spaced 60 feet apart, so their illumination is all but continuous. Secondary streets and alleys are not lit; it is common for citizens to hire lantern-bearers when going out after dark.

Alleys can be dark places even in daylight, thanks to the shadows of the tall buildings that surround them. A dark alley in daylight is rarely dark enough to afford true concealment, but it can lend a +2 circumstance bonus on Stealth checks.