Haunted Halcyon House, 3400 Prospect Street NW, Washington, DC, USA

Halcyon House was built in 1787 by America’s first Secretary of the Navy, Benjamin Stoddert and has had many owners along the way, leaving their ghosts behind them. Among them was Albert Clemens, Mark Twain’s nephew, who believed by expanding the property he could somehow escape death. He built strange staircases leading nowhere, tiny rooms and secret trap doors. However, this didn’t stop him dying in 1938. The building is considered to be Washington’s most haunted house.