Decades before the scandal, this staircase on the river was a literal "water gate."

A haunting tribute to pioneering photographer Clover Adams.

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

The first purpose-built art gallery in the United States is once again open as a center of craft arts.

Largest Roman Catholic church in North America.

The actual model from the original "Star Trek" series is now on display at the National Air and Space Museum.

The oldest continuously operating fish market in the United States.

The national park was once a plantation estate.

There’s a hidden military meme engraved on the World War II Memorial.

The beloved statue at the National Academy of Sciences is oh so inviting to sit on.

A three-story tower of books about Abraham Lincoln is one of the more unusual monuments to the president.

A hidden gem on the lawn of the U.S. Capitol Building designed by landscape architect Frederick Law Olmsted.

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

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

The United States Capitol's former columns still stand.

A super-sized promotional trick that is now a D.C. landmark.

This lonely waterfront memorial to the men of the Titanic was erected by the "Women of America."

Rumor has it the hot dog stand was targeted by two Russian nuclear missiles.

The remains of a historic plantation nestled in between a parking lot and the rental car return at Reagan National Airport.

This lovely picnic spot featuring thunderous jet landings is an aircraft spotter’s dream.

The romance of early commercial flight still fills this Art Deco destination.

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

America's first federal monument.

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