Once the supplier for noteworthy projects like the National Cathedral, this old brickworks now lies abandoned.

The United States Capitol's former columns still stand.

The most accurate timepiece in the world.

A super-sized promotional trick that is now a D.C. landmark.

Housing the National Women's Party since 1929, this historic house is now a monument to the fight for gender equality.

There just so happens to be a court even higher than the U.S Supreme Court: a basketball court in the building itself.

100 years later, they're still down there.

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

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

Home to items never before seen by the public.

This sandwich shop has a century-old elevator behind a sheet of plexiglass.

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

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

They sort through millions of dollars worth of diplomatic gifts on behalf of the government.

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

The "lovely red Vega" of the legendary record-settling pilot.

The most decorated dog of World War I is preserved in the Smithsonian.

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

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

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

The Pentagon is so large that it was planned like a city, complete with internal highway infrastructure.

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

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

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