This unassuming passageway played a key role in one of the most important events in U.S. history.

This restaurant has been a haven for D.C.'s LGBTQ community since the 1950s.

These abandoned waterworks are crumbling into the Potomac River.

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

A bas relief commemorates the "Nuns of the Battlefield" who cared for soldiers on both sides of the conflict.

Washington's top-secret Cold War-era doomsday communications tower is located in a small neighborhood park.

When it opened during the final years of the embargo, all the drinks and cigars were free.

This leafy estate is worth $18 million and is so grand it has two mailing addresses.

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

A lovely aquatic park built by a one-armed Civil War veteran who made a fortune from lotuses.

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

A monument in Washington D.C. marks the spot from which all other roads were supposed to stem.

A wondrous old library overlooking the nation's capital.

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

This grand gothic brewery has been pumping out suds for over a hundred years.

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