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

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

Light bulbs, scrap wood, and tinfoil comprise this homemade throne of the gods.

Home to items never before seen by the public.

The national park was once a plantation estate.

This stately mansion, built in 1787 by America's first Secretary of the Navy, is rumored to be one of the most haunted buildings in Washington, DC.

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

A wondrous old library overlooking the nation's capital.

At 207 feet, one of the world's longest continuous escalators.

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

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

An extensive, if one-sided, history of U.S. law enforcement's war on drugs.

A derelict bit of transportation infrastructure hidden in the woods.

These recently uncovered walls are all that's left of Washington, D.C's first defense contractor.

A former major munitions plant that has been converted into a sprawling art space.

Soldiers were buried next to Lee's house in the center of Arlington Cemetery to dissuade the general from reclaiming his property after the war.

An original apothecary from 1792.

The narrowest house in America is seven feet of pure spite.

The final resting place of an unidentified revolutionary soldier sits behind a Virginia church.

Remains of a historic fountain that was mysteriously lost in the demolition of a D.C. traffic circle.

The span is crooked and made from two older recycled bridges.

This fort down the Potomac from Washington, D.C. was once the only defensive fort protecting the capital.

Time travel with sweets across history at this research-based candy store.

The ruins of this long-abandoned unsuccessful gold mine can still be found.