I had once written down that there must have been a civilization which was able to cut the mountains into the platforms we know nowadays.

These could have been dwarves, but also some unknown civilization which also built the huge underground dungeons ...

When you find a big kettle of crazy, it's best not to stir it.
--Dilbert cartoon

"Interplay.some zombiefied unlife thing going on there" - skavenhorde at RPGWatch