This is a map I sketched a few years back, but never did the shading and release. As you can see, the map was based on a silly idea about petrified remains of a drake turned into a dungeon and a dungeon lying beyond that. The great drake was called Rephluxhia and even after its defeat it's belly is still filled with a pool of acid and noxious fumes.
After a quick shading I decided to include a couple of other versions I managed to make fairly quickly.