100 years later, they're still down there.

One of the last mosaic tile facades found in the city.

Sip creative cocktails in the former vault of the Riggs Bank.

This Masonic lodge was the first major private building to be constructed in Washington, D.C. after the Civil War.

Once home to the largest photo service in the United States.

Beneath unsuspecting visitors feet, a capsule containing pieces of America’s civil rights history.

The National Park Service’s best-kept secret with views that rival any in D.C.

The story behind this beloved toy—named for Theodore Roosevelt and owned by his grandson—is more complicated than you might guess.

The U.S. Army's giant warehouse of war art includes Hitler’s watercolors and Norman Rockwell oil paintings.

The legacy of a wealthy executive and his wife, this little-known art museum features works by Picasso, Monet, Renoir, Cezanne, and more.

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

This millstone-topped marker details the history of a mill that served as a landmark for both Union and Confederate soldiers during the American Civil War.

The hippo that stands on this university campus was once a drunken flea market purchase.

The "Key of Keys" for Washington, D.C. and the apocryphal landing place for the military campaign that started George Washington's career is now at the bottom of a well.

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

This historic boathouse was constructed using salvaged lumber from burned barns.

An 18th-century townhouse that once hosted guests of the president.

Before Metro, Washington had a robust streetcar network—and you see the remains of this infrastructure if you know where to look.

A wondrous old library overlooking the nation's capital.

Sit where JFK proposed to Jackie or where Nixon dined on meatloaf at this storied pub.

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

This small hilltop church weaves the urban history of Washington, D.C. with the national history of the United States.

This bridge over D.C.'s Rock Creek Park is sometimes called the "Buffalo Bridge" because of its four buffalo sculptures, which were cast from a single piece of bronze.

This Virginia town has been famous for its fried chicken since the 19th century.