The Octagon, Washington, D.C.

Ghostly doings have been reported since the mid-1800s in the graceful 1800 mansion that once housed the American Institute of Architects. One story concerns the original owner's daughter, who fell in love with a man her father disapproved of and jumped from the second-floor landing. She died "on the very spot" where a ground-floor carpet "keeps flinging itself back when there is no one about."