Three encounters in to second level on Athas. We followed an ankheg hole below the desert and have found ourselves in a dungeon of sorts. Up until this point it had all been rough hewn, possibly created by giant worms, but full of the dead who came back to life.
Tonight, though, we fought through a crystal spider web and entered an obvious dungeon, created by intelligent beings for a specific purpose. What that purpose was, we do not know. What we do know is that the crystalline creatures that were guarding the place are now shards beneath our feet.