The remains of a historic plantation nestled in between a parking lot and the rental car return at Reagan National Airport.

In the basement of the U.S. Capitol Building is a hidden storage room full of ornate floor tiles leftover from the 1850s.

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

Before Nixon, "watergate" meant canals.

This hollowed salt dome is the largest oil storage facility in the world, hoarding 250 million barrels of crude oil.

100 years later, they're still down there.

Disks are rolled out onto the south lawn to absorb the impact of Marine One's wheels like giant coffee coasters.

She stares out across six lanes of traffic, clutching a musket and infant with determination.

Four ionic columns from the Treasury Department building ended up in a park in Nebraska.

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

The school tested mustard gas for the U.S. Army during World War I.

The first presidential bomb shelter was located in an old vault under the Treasury, connected to the White House via tunnel.

There’s a special club house at the top for the bell ringers.

Literal "money laundering."

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

A line of blue paint marks the route of the inaugural parade.

About 80% of all U.S. avocados are descendants of Rudolph Hass's glorious tree.

The White House Situation Room was taken apart in 2006 and shipped to the Ronald Reagan Presidential Library.

This poor little statue is the most vandalized memorial in Washington.

Legend has it that President Grant’s frequent drinking in the lobby gave rise to the term “lobbyist.”

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

There's an old indoor swimming pool hidden directly underneath the White House Press Briefing Room.

The elevator that makes it possible to fly American flags in bulk over the U.S. Capitol

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