The Land of Nightmares, mostly referred to by the Noops as Viltheed, is the whole south end of The Sleeping World, with it's capital situated in the Mountain of Viltheed. It consists of Swampland, the Fire Rock Mine, and The Dark Side.
Zordrak and the majority of the Urpneys race reside in Viltheed, along with several other antagonistic creatures. The area is usually considered off limits by the heroes, only entering there to reclaim The Dreamstone whenever the Urpneys successfully steal it. However occasional conviniences exist in Viltheed. Mrs Blossom resides in Viltheed since it allegedly works as a better ground for making Dream Bubbles while some medicinal herbs also grow within it's caves.