A derelict bit of infrastructure from the canal that once ran through D.C. is landlocked in the heart of the city.

Look closely and you’ll notice that the color changes a third of the way up the tower.

This seemingly out-of-place gas station by the Watergate hotel was once described as the most expensive gas station in the world.

The preamble to the U.S. Constitution written entirely from vanity license plates hangs in the Smithsonian museum.

100 years later, they're still down there.

A museum cafe showcases Native American dishes and indigenous ingredients from across the Western Hemisphere.

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

A little marble compass above George Washington's (empty) tomb in the Capitol marks where D.C.'s four quadrants intersect.

The remains of Martha, the last known passenger pigeon, serve as a tool to educate about conservation.

Members of Congress have traveled between the buildings on Capitol Hill for a century hidden from tourists, press, and storm clouds.

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

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

The most accurate timepiece in the world.

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

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

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

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

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

A tiny piece of the Moon is embedded in this stained glass masterpiece.

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

Home to items never before seen by the public.

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.

Welcome to old Florida, where a 1940s mermaid show is still enchanting visitors.