800px-Lwt02830A few weeks ago, I went on a weekend trip down to Mammoth Caves in Kentucky. The cave system at Mammoth Caves is the longest known cave system in the world, comprising ~400 mapped miles of intertwining caves. That is 400 miles that they know about and have mapped. It probably stretches much, much farther and deeper. It was an impressive place, the 12ish miles of it that were open to people without a special spelunking license, and it left an impression on me. Relating almost everything in my life to gaming, as I am wont to do, I couldn’t help but think how much a little real world experience could be brought into gaming’s interpretation of caves. So here are 5 things I picked up from my trip that might improve your portrayal of caves in your games.


1. Cave Architecture Is Fascinating, But Not Always What We Think Of It As

The way most caves are formed is nifty, especially the type we tend to use in adventures, but they aren’t complete. We tend to imagine caves as great places that fit an adventure path, not an awesome place that just happens to be the setting for an adventure.

  • Sinkholes – Most inland (nonsea or lava) caves start with a big sinkhole. The area surrounding them is a deep descent down to the opening. That is, any opening large enough to really fit a person through. You can use the sinkhole to really describe how this is just the beginning of a descent. How the green slopes and wooded areas begin to tower over the adventurers as they descend to the cave. It sets the tone of “I’m going underground” really well. Also, cave entrance sinkholes are cold. The temperature in caves is significantly lower than the surface, so you are always going to get a blast of cold air when approaching the entrance of a cave.
  • The Initial Descent – Any cave formed from limestone (a good deal of inland caves) is going to be pretty far beneath the surface. Initial openings that lead down will be made of looser rocks, but the types of stable and large cave openings that exist are going to start about 140 to 200 feet down. That is about half a football field length beneath the ground you walk on. Getting into a cave might require a bit of a rappel or a steep descent.
  • Caves Are Not On A Single Flat Plane – Walking through the caves, there was a lot of gradient change and moving up and down. Consider this in your descriptions and in the amount of time it takes people to traverse relatively easy terrain. There will be a lot of slight up and down that might have movement modifiers.
  • Rocky Terrain Is EVERYWHERE – I was walking through a relatively well maintained tourist cave that tried to accommodate lots of foot traffic. But all to the left and right were lots of loose stone that had fallen from the ceiling. Caves are rarely in danger of collapsing, because all of the loose rock has probably already collapsed. Terrain may be hard going.
  • Similarly, You Have To Squeeze Through A Lot – There are many areas in a cave where it is really hard to build out a door or knock down an area, so in-between large cavernous rooms there are likely tight squeezes. If you like to play realistically, removing armor or transporting supplies through a squeeze is completely reasonable. It might take a small chunk of time, but that is the terrain found in many caves.
  • And Caves Are Often Home To Underground Rivers  – Stable caves are pretty bone dry, but they were formed by great rivers a long time ago. That means that there are probably areas of the cave where a nearby river still flows. This means you can have a great time adding a sudden unexpected water hazard for the party or a way for them to refill canteens on a long expedition. Plus, cave rivers look really awesome. Let’s not even talk about cave waterfalls.
This video shows a lot of the cave architecture and look.

There are plenty of fascinating geographical features to caves, and there isn’t enough time to talk about them all. But you can find a lot of great videos that can give you inspiration for new ways to portray caves in your adventures. It is almost unbelievable to think of how caverns look and feel. So seeing video of caves can really inspire you.

2. Everything Gets Preserved

Caves are dark, sometimes damp places, but often their lack of humidity and their standard, cold temperature makes for a perfect place to preserve things. The tour guides told stories of a native american body that was found inside the cave. Not a skeleton, the body. It had lost most of it’s mass and depth, but it was squishy and preserved. The tour guides also talked about ancient reed-woven sandals that were found inside the cave. An early 1900s entrepreneur tried to take them to the surface to sell to tourists, but they disintegrated in just a few days. The outside conditions made those fragile fibers decay at an incredible rate. However, wooden climbing poles that were found inside the cave and kept there were nearly as strong as they were when they were first dragged in, according to the tour guides. A sword or other sturdy material taken from a cave might not show much damage, but a very old wooden chest drug out might crumble after a days worth of exposure. It would depend on the age and type of material, but these are things worth thinking about. They can add to the flavor of the cave adventure and really show how different of an environment it is.

3. Candles Make Marking Cave Walls Easy

imageA fascinating thing about limestone caverns and cave preservation is that a candle’s smoke and small flame will burn itself in pretty permanently. A popular tourist past-time in the 1900s for recreational cavers was to put a candle on a stick and burn one’s name into the ceiling. This means that, in your game, messages could be easily and near permanently marked. A group of adventurers, or a skilled guide who suddenly seems really frigging impressive to the players, could mark paths with a simple candle and a few seconds work. The orc’s encampment could be gilded and stylized with really freaky markings, even if the orcs aren’t going to be that bright. The blast of a fireball would probably make a very vivid mark.

4. Creatures…

…are actually pretty absent from most deep caves, but the ones that do exist are pretty nifty.  Very few real cave animals make great monsters though, but you can use their presence to add variety to a cave ecosystem.


Cave crickets are pretty common in most caves around the world, and they are often mistaken for spiders.There are many types of insects that live in caves, especially near the surface. Millipedes, beetles, moths, cockroaches, etc. Insects adapted to caves are very much the creepy crawly type, but they are rarely slimy or wet. Dry caves have dry creatures.

IMG CC BY-SA 2.5 by Gunther Tschuch

Bats are very present in caves, but rarely get farther down, staying mostly near openings. They also sound very loud inside of echo chambers.

“Ridges have rabies!”

Salamanders, toads, and other amphibians can be found coming in through cave rivers. A great visual is coming upon a cave opening, hearing a rushing sound of an underground river, and finding a hundred salamanders choking the area around it. They might be albino, or they might be recent transplants who make it back to the surface every so often.


The inclusion of realistic cave creatures is a good detail for games. They can exist right alongside the albino bears, giant creatures, and other creations of pure imagination. They even validate the existence of such fantastic creatures. While most areas of a cave will be barren of life, some have their own entire ecosystems depending on the openings to the outside world, their depth, and what kind of adaptations the creatures have made. Here is a good site for some basic information on cave critters. http://www.adventure-caves-usa.com/cave-animals.html

5. Play Up The Darkness

Caves are really frigging dark. I mean really frigging dark. I was on a lantern tour, where 1 in every 3 or 4 people had an old oil lantern for light. And that was it. We could see okay… but not very far ahead. If I didn’t keep the lantern right at the bottom of my kilt, illuminating my feet, I could stumble very easily. I tried to get some video footage of how little it really illuminated, but cameras aren’t great in low light. This made me think of one thing. Ambushes would be really easy in a cave. A lantern held aloft will illuminate 20 to 30 feet out, realistically, but creatures that can move in the dark can see you really well and fire projectiles from afar. And you can do a lot psychologically with darkness in a cave, talking about how cramped it feels and how the human mind isn’t really ready for that kind of environment. At the least, if we adhere to most gaming conventions about light, we can talk about how big the rooms are and how you can’t really see to the edges. In fact, old guides use to throw “torches” (oil soaked bundles of rags) into corners to illuminate more of a cave room. This was the only way that many of the large caverns could be seen fully at once.


IMG CC BY-SA 2.0 by Jeff Kubina


Move to 5:40 or so when the lanterns are shown in the dark. In a cave, Your eyes will adjust and show you more light than this video will pick up, but, thanks to movies and media, we overestimate how much light a lantern or torch really gives.


There are a ton of fascinating facts and information about caves that you can use to enhance this pretty basic element of gaming culture, but nothing really beats seeing it in person. If you’ve got a tourable cave anywhere local to you, go check it out and see what I’m talking about. If you don’t, well thank the digital age. There are lots of great resources for getting inspired by caves. Here are just a few:


Hopefully I’ve gotten you thinking about some of the more realistic, but less explored details of caves. My goal here is to inspire some of the natural wonder that real caves elicit. There are lots of resources out there to garner some new details and inspiration from, and many different types of caves that operate in many different ways. So go searching some inspiration and information on your own. What do you think about caves in RPGs? Do they rarely feel realistic or fantastic enough? Do you prefer the more straightforward approach to caves without a lot of the realistic complications and features? What kinds of fun features have you thrown into cave based adventures?

26 replies
  1. shortymonster
    shortymonster says:

    Yay, reality used in role playing! http://shortymonster.wordpress.com/2012/07/30/to-be-an-archer-3/
    Sorry, I just love using my History degree.

    Not exactly caving, but if you live near a coal mining museum, I did a summer internship at one in Wakefield, UK a couple of years back, they do underground tours that are just as good at giving you an idea of the darkness. hell, it was so scary in places, especially when you’re told of all of the things that can, and have, gone wrong, it inspired a big section of my last horror game. http://www.ncm.org.uk/

    • John Arcadian
      John Arcadian says:

      Mining is fascinating as well and could constitute a whole separate article. Mines have an entire different architecture and ecosystem that can provide a lot of fascinating, but often overlooked, details.

    • Roxysteve
      Roxysteve says:

      Yeah. I was taken on a tour of a defunct Gold mine in Wales before you lot were born. Most impressive were the “straws” – thin, hollow stalactites of iron oxide that formed on freely flowing dribbles of leeching groundwater pouring through the ceiling, forming pipes for that water to flow through. We are talking about quite a rapid flow here too, not the drip, drip, drip of limestone stalactite formation. Must’ve been hell to work in that environment.

      The spoil tips outside were all dead areas because of the lethal chemicals used to recover the gold from the ore, and there were small, deep-colored pools of highly toxic water from the run-off. Chernobyl had nothing on this – it was Geidi Prime levels of polution.

  2. Tsenn
    Tsenn says:

    Oh boy, I could really have used this a month ago! As it was, our intrepid Rogue Trader band progressed through some freehand-drawn caverns and then into a dense network of lava tubes (not illustrated). Playing up the darkness worked, until they went in with personal night vision and a small army, all equipped with flashlights.

    On the one hand, they were quite clear about being in a cave complex, so that part worked fine. On the other, the relatively linear nature of the place took away from the potential mystery and sense of exploration. To the players credit they were smart about it, using swarms of cable-linked servo-skulls to help map their advance. It seemed right to give them that as a win, and focus more on the challenges within rather than the caves themselves.

    • John Arcadian
      John Arcadian says:

      That sounds eerily like (minus the servo skulls) how we were told many of the caves were mapped. Running out cables, making sure there were good markers on them, setting up waypoints. Cave exploration in a modern setting can be very different, and it sounds like you ran a good game with caves. I’ve rarely thought of it in a futuristic setting, but alien caves on alien worlds is sounding fascinating as a concept.

  3. Svafa
    Svafa says:

    I’ve done a lot of research more recently on cave environments as our campaign’s current home base is well, a town under a mountain. Being a town, it’s a little different, mostly in the fact that wildlife is more prevalent.

    One of the coolest things I stumbled upon that I had never really considered was that ferns, mosses, and algae can grow in lighted caverns. They’re actually a big problem in a lot of caves, as the plants will gradually weaken and destroy the stone forming the cave. Granted, if you don’t have permanent lighting fixtures then there isn’t an issue, but in the case of an underground town or city… So our town has moss growing alongside fungi on the walls, floors, and ceilings of structures, while small ferns proliferate around the underground river supporting the town.

    Additionally there are a lot of cool (and exotic) cave critters, like birds that use echolocation, snakes that climb walls and cross cavern ceilings to get at bats, and so on. Add in a functional town, and you can reasonably expect to find critters deeper than typical as well, small rodents, foxes, cats, and various scavengers. And lots of insects, which easily leads to a bat population that lives entirely underground.

    • John Arcadian
      John Arcadian says:

      The underground town sounds awesome! I kind of want to do an article along those lines. The less realistic, but more awesome sides of caves. Things that don’t really occur in most caves (like bats completely underground, but I could be wrong about that) but that could occur with the right conditions.

      • Svafa
        Svafa says:

        I’ve been treating the town as though it were built at the entrance of the caves. I’m sure that’s not the most realistic treatment, but as a guideline on the sort of creatures and interactions you might find, I think it works well enough.

        Since the ecosystem is supported by the town, it’s also been fun to figure out how the town interacts with the wildlife. For instance, everyone knows that dwarfs eat rats, but not many realize the soup served at the dwarf king’s wedding was made from the nests of cave swifts.

  4. Roxysteve
    Roxysteve says:

    A great article on a subject dear to my heart, though what I need is a follow up on how to present this so players get the point rather than “the hump”. I love caves but have trouble conveying the raw emotion of such places to people sat at a table in broad daylight munching Pringles.

    If anyone is traveling in the UK near Bath I can’t recommend strongly enough a tour of the caves in Cheddar Gorge. Probably over-commercialized now (I went about 48 years ago) but I still remember parts of the Gough’s Cave tour (pronounced “Goff’s Cave” in my day). To be in the area and to miss touring at least one of the cave systems is to go round the moon but not land even though you have a Lunar Module to hand and fuel and supplies enough.

    Also well worth a visit is Wookey Hole which has a magnificent limestone “Witch” feature and lots of underground river to see in action.

    For me a key experience in cave touring was to come upon an underground river crossing our route that was absolutely crystal clear and absolutely devoid of life (which is of course why it was so clear). Nothing so creepy as a pitch dark place with a flowing but dead river in it.

    Gough’s Cave (I think; old brain might be playing tricks and if not Gough’s Cave it is in Wookey Hole) features a reflecting pool in a raised “crater” or bowl set in a wall at about chest level in which the stalactites reflected in the water seem to form a village from non-existent stalagmites. It was so memorable that I’ve put it into a couple of caves in my games.

    Easy stalactite/stalagmite orientation mnemonic for cave-oriented GMs: “Tites hang down”

    RPG Resource: The D20 Conan game, now OOP but still available, has a supplement “Catacombs of Hyboria” devoted in part to creating and running parties through natural caverns and caves, and is well worth a look to interested GMs. Don’t pay silly money for one though.

    Also, National Geographic has, in the last two years, run an in-depth article on a cave system in South America. I can’t remember the issue but have it somewhere. The isomorphic cut-away diagram is a study on how to visualize such things that bears study, and the article is very interesting from a “what does it take to penetrate a cave system” point of view. Not a walk in the park by any means.

    RPG story: I once did a cave dive for a Call of Cthulhu game in which I wanted to show the players why the maps shouldn’t dictate their levels of assurance. I bought several sets of dungeon “tiles” (not the squared affairs one gets today but more natural looking ones in a buff-on-black color scheme), and laid out my cave complex that included one really big cavern on a sheet of plywood upon which I had glued black craft paper it suggest the rock mass surrounding the caves. The resulting map would be what the players would move their 25mm figures through.

    Then I covered the entire thing with small overlapping sheets of black craft paper to hide the details. I made some sheets of the same size as those covers with triangles cut out to the stated range of flashlights in the rules, and others with a circle cut out to represent lantern light.

    As the figures moved through the caves they were forced to see only what was visible through these cut-outs depending on the light sources they used. Not only that, their knowledge of the route behind them was virtually nil as it fell back into darkness and I covered it up. This caused some dismay and an “aha” moment in the players.

    It was very labor-intensive, but it paid off when they got inside the cavern where their lights would not reach both sides at once no matter how they panned them around.

    The players actually panicked for real at that point, inventing scenarios for ambushes faster than I could keep track of them, and they ended up lost in the middle of an open space for the longest time as their priorities narrowed from “explore the cave and recover the idol” to “find a bloody wall before we get jumped!”

    It was lost on no-one that the bad guys probably would not need lights, but would find those of the PCs to be quite attention getting, and it required no warning from me (and no subsequent argument) either.

      • Roxysteve
        Roxysteve says:

        Heh. My wife made me wire new lights in our unfinished basement last weekend. While I was moving some stuff I came across a bag filled with the specially cut bits of black paper from that game.

  5. CalebTGordan
    CalebTGordan says:

    I have actually taken caves I explored in Eastern Kentucky and mapped them out for games. One of them had a flood trap that almost killed the party.

    A few dangers that are easy traps in caves:
    – Sudden pits. With the light levels it is easy to think the shadow you are stepping into is just a shadow. A few times in my experience I came close to making a step I wouldn’t have survived.

    – Cornering wildlife. While deep caves don’t often have large wildlife, shallower and smaller caves might. I have been in a few caves that showed signs of coyote, and a couple times we decided not to squeeze past some rocks because of the possibility of one being back there.

    – Deceptive water levels. In the caves I explored, we had to wade through water to reach certain parts of the cave. Because of the light levels and the swiftness of the water we couldn’t gauge every step accurately and a few of us ended up waist deep in the water. Couple this with powerfully swift moving water that drains into a submerged cave and you have the danger of drowning and never being found again.

    – Water Dangers. This doesn’t happen year round in caves with water. Caves with underground rivers can have higher water levels, powerful currents, and sudden floods in the rainy seasons or in the Spring when snow melts.

    • John Arcadian
      John Arcadian says:

      Very nice. I didn’t get into the underground rivers too much, when I went, so these are some things I never would have thought about. What is it like to be exploring and come upon a river?

      • CalebTGordan
        CalebTGordan says:

        In the cave we explored there were a few places with water. We were there just as the water levels were about to reach their lowest and we could see signs that the water had once reached several feet higher. I actually went back later in the summer and some of the spots that had water before were only damp.

        There was only one place in the cave that I could call a river, the rest was clear, calm, standing water. The river shot out of one section of cave with great force and flowed out of one of the many exits to the outside. The water wasn’t so powerful closer to the exit and we were able to cross.

  6. BryanB
    BryanB says:

    Very informative John. I have been in the Timpanogas cave complex in Utah. We went during the summer but had to don jackets inside of the caves. I found this little fact from their website fascinating: “Even though temperatures can be below freezing in the winter at Timpanogos Cave, the caves keep a fairly constant temperature of 46 degrees F and 100% humidity.” The air in the caves was very cold and moist.

    I once had a friend that complained about how I handled a D&D combat scene in heavy woods at night. He thought the modifiers being applied were too harsh. My family used to have a cabin up at Camp Sierra above Shaver Lake in the Sierra Nevadas. He was able to join me for a week up in the mountains one summer. At night, a bunch of us would gather around the cabin’s table and game. A discussion ensued about that D&D game with a night combat in the forest. So we all went outside to demonstrate. Taking positions that were roughly how the combat was laid out in the game, I said, “So, can you see why the modifiers were applied the way they were, in heavy pine forest, at night, with little moonlight?” He said, “I can’t even see you and you’re less than fifty feet from me.” I said, “Exactly.” 🙂

    While I don’t nitpick “realism” in a game system’s mechanics, I do like to borrow from the real world for depth and flavor when using any game system. Experiences like trying to see in a forest with little or no light, or exploring a cave complex can add a lot of descriptive details to the game. No doubt about it.

    • John Arcadian
      John Arcadian says:

      Agreed. Realism is sometimes a damper to fun, but it really can enhance a scene or combat when used appropriately. People sometimes have problems getting how a situation would play out, but a great real example like that can show them why they’re getting a penalty or their character would know enough not to try something that will kill them.

  7. Kitchen Wolf
    Kitchen Wolf says:

    The Ape Cave on Mt. St. Helens in southern Washington is a lava tube made of volcanic iron. The floor is covered in a reddish slime (moisture, microbes, and rust), and consists of ruts that are more or less the width of a human foot. Wouldn’t be a whole lot of fun to maneuver quickly in. Iron ore is a nasty thing to trip into. But the biggest thing that strikes you is the dark. The kind of dark that results from sunlight not making the slightest impression on several hundred yards of rock and makes you wonder if you’ll ever see again. Losing the light source means groping your way home by hand for a couple of miles, which just isn’t happening.

  8. Kurt "Telas" Schneider
    Kurt "Telas" Schneider says:

    Inspiring article. There are a couple of caves here in Austin that I now need to go see…

    To convert caves to a fantastic setting, just add a food source. I’ve used Twilight Crystals, which are glowing crystals that actually grow over time (given the right minerals and environment), and provide energy for low-grade photosynthesis. Another possibility is a fungus that ‘digests’ rock (very slowly) into an edible mushroom.

    Once you add a food source, the underground can easily be populated by the Big Scary Things that our imagination would like to think lurks in the darkness.

    • Roxysteve
      Roxysteve says:

      Actually I think it is worth pausing for breath before you do that. Everything discussed here is about the atmosphere and inherent dangers in a cave. Put some bugbears (or whatever) in it and it falls back into being a dungeon and there goes all that lovely effort.

      I think, and for what it’s worth I’ve used this technique to good effect, that the cave system should be used for getting to somewhere the regular cast of thousands can be found rather than housing them. The cave system itself *is* the encounter.

      After all, the bad guys are just like the players should be (but so often aren’t): comfort-seeking things looking for a safe, warm, dry place to sleep where there is adequate light and food to hunt/gather. The caves discussed here are not that for anything but the smallest animals, and even the bats sleep only in the outer parts with access to the outside for hunting.

      • Kurt "Telas" Schneider
        Kurt "Telas" Schneider says:

        The cave as encounter is fine, too, but some of the groups I’ve gamed with would get quickly bored with it and look for something to fireball.

        Besides, that oppressive darkness, the claustrophobia, the discomfort… How much more intense would it be with the sound of something BIG breathing in the distance, or if you found the remains of something with huge chunks torn out of it?

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