Very dark and inhospitable place made predominantly for dungeons. In the dungeons you can find some treassures but they are always guarded by strong monsters. You can not mine or build here.
Enterance to Nether Fortress is located at the end of east hall in Nether. You can find some treassures there but they are guarded by monstres stronger than the ones in Overworld dungeons.
Pigman Village is a small village inhabited by Pigmen located behind Nether Fortress. An entrance to a Prison is located there and you can also find a villager that gives you Ingredients quest there.
The Nether Cave is located at the end of south hall in Nether. It's full of skeletons which drop white essence when killed and you can of course find some treassures there. At the end of this cave is a Death's room.
„Nikdy se nesměji nejlépe. Bojím se, že by to mohlo být naposledy.“ Jan Werich