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

This bell is one of the last remnants of the lost city of Triadelphia.

A diminutive plaque recalls the treetop sniper who almost killed Abe Lincoln.

Long-abandoned trolley tunnels just a mile away from the White House are turning into an art space.

A gorgeous mural outside a beloved D.C. restaurant pays homage to famous Black Americans.

The first memorial dedicated solely to the Black troops who fought for the Union.

The former home of Lillian Evans Tibbs and her grandson, Thurlow Evans Tibbs Jr., whose prodigious contributions to music and art spanned more than 90 years.

Washington D.C.'s most famous pianist, composer, and bandleader still tickles the ivories outside Howard Theater.

The former home of the woman who successfully fought to integrate restaurants in Washington, D.C.

The world's oldest soul food restaurant is also one of its best.

A cavernous three-story, 43,800-square-foot basement that was forgotten about for 60 years.

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

An overlooked memorial honoring the local Washington residents who died in World War I.

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

There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

Washington's iconic carousel has a nice piece of Civil Rights history.

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

Part of a WWII submarine is lurking outside the Washington Navy Yard parking lot.

Outside the Department of Transportation, a collection of artifacts honors the history of how we get around.

The discovery site of the "Capitalsaurus," the official dinosaur of Washington, D.C.

A secret greenspace hides atop a Capitol parking garage.

One critic described it as "middle Mussolini, early Ramses, and late Neiman-Marcus." Another called it an architectural "natural disaster."

"Congress may voluntarily remain in session throughout the summer, in order that our Congressmen may be protected from the intolerable discomforts and dangers of the ordinary outdoor weather!”

The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.