On Caves

I'm a sucker for theme parks. It's a surprising aspect of myself that I've come to accept. Anyway, I live about 2 hours away from one called Silver Dollar City. A fun fact about it is that it didn't start as a theme park, but rather as a cave tour. The theme park was built to entertain the folks who were waiting for the cave. Now folks don't even realize there is a cave to explore under the roller coasters.

Go figure.

Anyway, I took the tour and my mind was flooded with ideas for making caves interesting in RPGs. Here is a collection of ideas, thoughts, and other odds and ends about caves.

Caves Are Vertical

When designing underground or cave like dungeons, lairs, and such, draw the map from the side instead of the top.

The changes in elevation could be sheer cliffs, gradual inclines, winding hallways, corkscrews, or even odd things like a drop with a large dome, debris pile, or stalagmite to navigate around on the way.

Drops could be anywhere from a few feet to several hundred feet. The walls could be slick or made of easy-to-climb formations.

Light

Caves are pitch dark. This should be a threat to many players entering a cave. A typical adventuring party with torches or lamps will need to take care that they relight prior to their equipment burning out and that it doesn't get wet. Dropping a torch on the ground to fight should have a chance to go out since most caves are damp and wet. The same is true for navigating any water in a cave.

Should someone find themselves without light, finding things in their pack will take time. Nobody is used to doing things completely blind. Also, consider that as someone fumbles in the dark to find a torch, flint, and steel they are likely going to drop things on the ground which may slide away.

If a player tries to find their way out in the dark by touch, it would be reasonable for the Referee to begin and make rolls about which direction they go. Furthermore, the speed at which they travel will be extremely slow and the chances of bumps and bruises would be extremely high.

Finally, for many players in the dark, they are helpless prey and the sounds of them trying to gain light would be easy for creatures to home in on.

Passageways

Caves are full of amazing rooms and structures, but also connected by notoriously hard to navigate passageways and "squeezes." It should be exceptional that any human can walk upright between these larger rooms or fight without impairment.

The passageways should be full of twists, turns, low ceilings, force the players to walk sideways, and even crawl on hands and knees.

Keep in mind many players are wearing armor, packs, belts, weapons, and the like which all may get caught or cause them to be too large to squeeze into passageways.

Navigating in a cave that is inhabited should present the players with a keen sense of unease in passageways as they will be at a significant disadvantage.

Water

Caves are made by water so most caves will feature at least one underground water source flowing. This water is icy cold and with the combined environment of caves typically being chilly, getting wet could lead to fatigue or worse.

The damp nature of caves also means that the ground will always be wet and slippery.

Also, passageways are often going to have water flowing in them which will present the players with a dilemma to head into confined places with water without knowing if it'll be safe on the other side.

Finally, pools of water in caves is perfectly still and almost impossible to discern. This could represent a simple trap of falling in. Pools could be dozens of feet deep and have no visible clues that it is so since the water is so clear. A misstep could result in a heavily armored fighter sinking quickly.

Sound

Caves are made of stone, so sound will carry and echo. This should provide an interesting environment for exploration as the sound of running water and other things may be ever-present but almost impossible to pin-point.

Consider that if the cave is inhabited by creatures there may be constant sounds of them, but it would not be obvious how far away they are. The same is true for the players moving around. This interesting property of echoing sounds could easily create the sense of unease as everyone knows there is something deeper down.

Air and Temperature

Caves are almost never sealed but represent long passages for water to travel underground before exiting somewhere else. This means that caves often have a constant flow of air. In smaller passages this may become more intense.

The airflow will generally be cool as the temperatures in caves remain chilly almost always. However, magical caves may not have the same properties and inhabitants may also produce warmth in other ways.

A wet character is likely to get chilled quickly in a cave. Again, a prepared party that has time can address this easily, but a party in a hurry may wind up in a significantly worse situation.

Dangerous Gasses

While the majority of caves have breathable air, there is huge risk for there to be pockets of very dangerous gasses built up in rooms or in the bends of passageways. Carbon dioxide, for example will sink to low places and has no odor and suffocate people quickly.

Consider adding pockets of dangerous gasses as a trap. Some may suffocate, burn, cause confusion, or be highly flammable.

Creatures and Their Variants

Caves are full of life! When designing a cave be sure to include it. "Real" caves often have salamanders, bats, insects, and may even have unique species.

More than that though, caves offer a natural shelter to any other creature out there and so you can freely put just about anything into a cave.

Some real-life creatures that make exceptional inspiration for caves are:

• Crabs
• Salamanders
• Bats
• Assassin bugs
• Spiders
• Glow worms
• Slime molds

Variants

Let's make it more interesting though and take a normal creature that has evolved or become magically altered to survive in a cave. These creatures will typically have dark vision, echolocation, or something like tremor sense. They will be able to climb the slippery surfaces of the caves to move around as well.

Often cave creatures have lost almost all pigmentation in their skin and so you may want to incorporate that into your cave-dwelling variant. Also, many creatures eyes become very large or are nonexistent.

Finally, cave-dwellers live in a closed ecology so they are adapted to hunting in the dark. Almost all are able to navigate in near silence and remain motionless to ambush their prey.

Taking these into consideration you can take a normal creature and add these characteristics and you suddenly have a cave-dwelling variant.

Formations

One of the most fascinating parts of caves are its formations and any good cave location should have interesting formations. Some general guidelines are that many cave rooms feature one type of formation you do not need to hold to such a rule. Also, formations can exist in passageways as well.

Some tables to help you generate some are below these descriptions.

Rock Formations

These are typically structures made of limestone deposits and are the most common by far. For your game you may also want to consider the possibility that these formations are made up of something more than traditional limestone and carry unique properties or value.

Stalactites, Stalagmites, and Columns

Spikes that hang from the ceiling are stalactites and ones rising from the floor are stalagmites. When two meet it forms a column.

Stalagmites can form a hazard as they are spikes on the ground that can represent difficult terrain or the equivalent of a spike trap.

Stalactites form a hazard as they could easily fall from the ceiling causing serious damage to those below.

Columns also can present a hazard as they may not be large enough to withstand much damage and can fall like a stone log onto someone.

Curtains

A rather unique formation that looks like curtains of cloth hanging from a ceiling. They can be very large singular sheets or countless rows sometimes looking like hanging fish or meat. They are razor thin and if disturbed could fall and slice into those below.

Dome

These are large bell like shapes that are often large and rounded. They pose no immediate threat, but are slippery to climb and provide excellent cover and or opportunity for surprise.

Crystal Formations

By far the most fascinating type of structures found within caves, crystal formations are delicate, intricate and full of wonder. You may want to consider adding unique properties to these crystals to add mystery and wonder to your games. Some ideas are found below with the charts.

Stalactite and Stalagmite

Larger crystals can hang from ceilings or rise up from the floor just as rock formations do. Their edges may be sharp, and can fall, topple, or skewer unaware folks.

Needles

Long, impossibly thin crystals can exist in clusters just about anywhere. While incredibly delicate they are sharp enough to pierce most skins and hide. As a trap, they leave their long thin crystal needles embedded in the person, but a party may find clever uses for them.

Scales

Small rough formations can form on the sides of others that look like the rough interior of geodes. These formations catch light and are beautiful, but highly abrasive. Should someone rub against one of these formations it could easily cut into them.

Coral

Coral like structures grow in odd shapes. They can grow in tree-like shapes, cones, and any other shape. They are often formed by countless tiny crystals.

Contact with coral like structures behaves like needles in that they will embed in skin and require someone skilled in healing to remove.

Quests and Adventures

Caves are a type of environment, but why would a party mess with the risk of going inside?