The sci-fi villain is a little-known inhabitant of the U.S. capital's largest cathedral.

People escaping slavery may have hidden inside a corpse vault.

Fittingly, America's museum of architecture is itself a magnificently designed old building.

A piece of the Ludendorff Bridge, also known as Remagan Bridge, calls this military base home.

A blank headstone topped with a pile of pennies marks the final resting place of the infamous assassin.

The trials and tribulations of marking Poe’s grave.

This bug-eyed water wheel uses the power of the Sun to clean up Baltimore Harbor.

This abandoned asylum was once a state of the art facility before devolving into one of the most deadly mental institutions in American history.

A painfully obvious spy house sits right across the street from the Russian Embassy.

The most accurate timepiece in the world.

When it comes to handsignals (and colonialism) rock always beats scissors.

Also known as the Founding Church of Scientology.

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

America's Most Wanted's set resides in this tribute to the history of crime and punishment.

An atomic bomb-proof strongbox protects the U.S. Constitution from terrorists and thieves.

This isn't your average roadway—it's actually a National Park and a transportation pioneer.

A gift from Scotland to the United States in memory of the 270 lives lost when Pan Am Flight 103 exploded over Lockerbie due to a terrorist bombing.

Built to defend Washington D.C. during the Civil War, this fort became a post-war nucleus for a thriving Black community.

Once forgotten and built over, this historic Black cemetery now houses a poignant memorial.

This rare triple-jurisdiction drawbridge passes through Virginia, Maryland, and Washington, D.C.

The 72-foot giant escaped confinement in a large patch of mulch only to be reburied in the sandy shores of the Potomac River.

One of the largest artillery pieces in the world sits in a Washington D.C. parking lot.

An oft-overlooked, magically musical monolith that stands majestically between Arlington Cemetery and the Iwo Jima Memorial.

A whopping 14,000 copper coins cover this miniature fighter jet.