Shadowfell

The Shadowfell is a paralell dimension to The Material Plane and occupies roughly the same space. Natural features of the material plane are reflected here, though typically distored and colorless.
"The Shadowfell, also called the Plane of Shadow, is a darkly lighted dimension, a world of black and white where color has been leached from everything. It is a place of toxic darkness that hates the light, where the sky is a black vault with neither sun nor stars." - The Player's Handbook