The house where John Wilkes Booth conspired with his co-conspirators.

Daredevil repair workers can worm their way out the access hatch, loop ropes over the apex and rappel down the monument.

A line of blue paint marks the route of the inaugural parade.

Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

An overlooked oasis of quiet on the grounds of Washington's monumental basilica.

An Industrial Revolution-era public work that purified water using nothing but sand.

This forgotten boat elevator was an engineering marvel in its heyday.

These figures float and flutter in this fountain crafted by famed Swedish sculptor Carl Milles.

Ship skeletons haunt Baltimore's waterways.

An intricately designed junk art house with four extravagant junk art cars hidden in the suburbs.

Franciscan monks created a facsimile of the Holy Land for North Americans who couldn’t afford the trip overseas.

The oldest building in the District of Columbia was preserved because of a mistaken connection to George Washington.

The little-known, 300-year history of the area includes former lives as a bustling tobacco port, parking lot, and industrial dump.

A small token of gratitude from freezing cold journalists who were given a warm haven while covering JFK's inauguration.

This stately mansion, built in 1787 by America's first Secretary of the Navy, is rumored to be one of the most haunted buildings in Washington, DC.

You could be standing at the site of one of D.C.'s most fatal tragedies and not even know it.

The site of the climactic scene from the classic horror film is now a historic landmark.

Giftshop catering to cryptozoologists and anyone with a sense of humor.

A historic estate packed with George Washington's heirlooms, and its own nuclear bunker.

Hellam Township is reputed to feature seven remote gates, which when passed through in the right order, open an entrance to hell.

A building shaped like the Army Corps of Engineers logo, because why not?

A wondrous old library overlooking the nation's capital.

There's a crumbling old mansion inside the Smithsonian National Zoo.

These recently uncovered walls are all that's left of Washington, D.C's first defense contractor.