A possible dungeon area I'm thinking on using for my Game Night game: the infamous crashed spaceship. Smaller than needed for a full-on campaign, though I'm looking at a few other ship designs that could be Undermountains in their own right.
Ship design stolen from the Myrmidon from EvE Online, a game I've never played, but they got some solid spaceship designs. One of the side bits flew off during the crash, which you can see in the left of the image. A good third of it is buried deep underground.
Anyhoo. I'm a proponent of throwing piles of the sci-fi peanut butter into my fantasy chocolate, so this is up my alley. Maybe it's up yours.
Heh. Up yours.
Myrmidon (c) Whoever owns EvE Online. no attempt at copyright claims being made.