The city I’m making is in a large underground cavern, very wide and open and I want to know what the housing would be like. This city is not exactly futuristic but definitely industrial. Late 1800’s to early 1900’s technology. The cavern is cylindrical, and widens near the surface. I was planning on having things like housing and markets and so on near the top. I want the houses to be practical as in efficient in spacing, allowing space for many other houses and for work. This city is based off of mining and would the houses hang from the ceiling like stalactites? Or be dug into the walls of the cavern?

  • $\begingroup$ Well it depends on what your going for. Do you want the housing to be efficient, look good, be cost efficient, be space efficient, or something else? Please clarify your question by editing it. $\endgroup$ Commented Jan 18, 2023 at 22:35
  • $\begingroup$ Please provide some more details. "Not exactly futuristic" - does this mean that today's technology can be assumed? What building materials are available? Is there a requirement for the main floor of the cavern to be used for a particular non-housing purpose? (The easiest solution for housing is just to use the floor of the cavern with privacy screens - why tunnel or build suspended dwellings unnecessarily?) How big a cavern are you talking about here - for a "city" it sounds like a dome kilometres across? $\endgroup$ Commented Jan 18, 2023 at 22:35
  • $\begingroup$ I apologize for the lack of information, I’m pretty new here so I didn’t know how to phrase the question. I want the houses to be more practical than anything. Something that would be allow a lot of extra space because this city is based on mining. Also, due to things like flooding I was wondering if they would have hanging houses. The caverns shape is cylindrical, but the closer to the surface the larger the area gets. I was thinking of having the “city” space near the top, with the more mining space near the bottom. Most likely be efficient, specially with materials and space. $\endgroup$
    – Spider
    Commented Jan 18, 2023 at 22:51
  • $\begingroup$ Actual underground towns and neighborhoods exist, why are those not to your needs. momondo.com/discover/secret-underground-cities-in-the-world $\endgroup$
    – John
    Commented Jan 18, 2023 at 23:13
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    $\begingroup$ "Cylindrical and widens near the surface"? Does it have an opening to the outside at the top or not? If not, there will be definite issues with ventilation in that cave, leading to no city being possible. $\endgroup$
    – Vesper
    Commented Jan 19, 2023 at 9:39

3 Answers 3


Paper Walls

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The cool thing about living in a cavern is you are already indoors. The cavern is a big house that protects us from the elements.

No need for a roof or structural walls inside the big house. Just walls for privacy. Make them from paper or wood panels. Maybe straw bricks to absorb sound. Nothing fancy.

Perhaps the bank and the prison are more robust. The bank is built from wood and stone blocks quarried from inside the cavern. The prison is built inside what used to be the quarry. We thought ahead and made a single tunnel that widens out. The prison is very secure.

  • 4
    $\begingroup$ And then Larry, who's been told time and time again that alchemy isn't real, mixes nitrates with something he's absolutely sure will make him rich... and the entire city burns to the ground in seconds. +1 for simplicity, though! $\endgroup$
    – JBH
    Commented Jan 19, 2023 at 0:30
  • $\begingroup$ @JBH Larry goes to jail and it takes them the rest of the week to rebuild the city. $\endgroup$
    – Daron
    Commented Jan 19, 2023 at 10:07
  • $\begingroup$ Not much wood growing in caverns. Apparently, there is a lot of stone growing there, though. $\endgroup$
    – Burki
    Commented Jan 19, 2023 at 10:21
  • $\begingroup$ @Burki Get the wood from outside the cavern. $\endgroup$
    – Daron
    Commented Jan 19, 2023 at 10:37
  • $\begingroup$ @Daron you mean while you're already outside to get rid of all that pesky stone? :-) $\endgroup$
    – Burki
    Commented Jan 19, 2023 at 10:43

Brick tenements

enter image description here


Brick tenements were the working class housing in densely populated cities at the turn of the century. Brick will last forever in a cave. Moist conditons in the cave will make laundry lines less effective but brick will not rot like wood. You can stack up little apartments on top of each other. The buildings can sit on the floor of the cave. You might be able to stack a little higher using the rear cave wall for support. The turn of the last century was when skyscrapers were being developed; a steel frame will let you build with brick 1000 feet high.

I envision the entirety of each cave wall being tenement front windows maybe with a balcony. Each unit is a long rectangle extending from the window back to the cave wall.

A central stair shaped like a double helix would be cool - one side for up and one for down. Dumbwaiter type elevator in the central shaft.



  • 2
    $\begingroup$ This is especially useful if built floor-to-ceiling to help shore the cavern roof. $\endgroup$
    – JBH
    Commented Jan 19, 2023 at 0:31
  • $\begingroup$ I really wonder what should the lighting be in that cave. Building an underground city without any light source inside first does not require windows, and second makes its inhabitants blind but have acute hearing over time. And in 1900 gas lighting was abundant while electric lighting only started to emerge. Too much gas and your city dies off due to no oxygen. $\endgroup$
    – Vesper
    Commented Jan 19, 2023 at 9:34
  • $\begingroup$ @Vesper I suspect they are bat people or olm-people or similar blind cave-dwelling hybrids. $\endgroup$
    – Daron
    Commented Jan 19, 2023 at 10:08
  • $\begingroup$ @Vesper over a very, very, very, long, long, long time. Your point about oxy is dead on, though (pun intended). $\endgroup$
    – JBH
    Commented Jan 19, 2023 at 10:49

This answer is a little tangential to your question, but your conditions have several issues (some were already pointed out by others):

  • A cavern that gets wider towards the surface would have its roof collapse. There is no depth where this problem goes away, since the weight/pressure on the roof increases
  • A closed cavern has severe ventilation issues
  • Drainage of water and waste
  • If your cavern is deeper than the water table (and thus doesn't need to be drained as heavily), then you run into cooling issues.
  • 1800s humans wouldn't build a city underground without really strong reasons

One suggestion for the last point is to consider a combination of:

  • Kimberlite pipes: a thin tube of rock that originates from a magma chamber that bursts to the surface, often contains diamonds and other minerals not found in the surrounding crust.
  • Very high surface winds: achievable if you have a mountain pass that funnels normal wind to very high speeds.

If you have a wider surface than floor, then building into the rock on the perimeter makes most sense for protection from wind.

If you have a narrower surface than floor, then your idea of hanging makes more sense, in which case you could do quite a lot of world building around suspended structures. However, you'd be far more constrained by weight, and building out of wood and paper makes sense.

Either way you'd need to consider drainage and waste-disposal though. (Wouldn't want that long-drop to land on a miner's head)


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