Svartalfheim
Svartalfheim is the dark resting place of the Dark-elves. You find the entrance to Svartalfheim inside of Gnipahellir, which is an obscure cave on a mountaintop. When in Svartalfheim you are literally inside Ymir's flesh. This, being the resting place of the Dark-elves, is full of their remains, maggots.