Well the dark is 'dark' because no light is let in. Places like an enclosed area with walls and ceilings also no lights are dark. It is dark because no light can get through the enclosure you are in.
i don't whant to be mean but this is not a real question because dark can just go and go ect........ Dark is when you cannot see your hand in front of your face.
It is definitely "People Under the Stairs". (different person) i myself actually think it is tales of the crypt. (another person) there was a book about skeletons with this begining. i think it was...