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.

While most wind tunnels test scale models, the "Cave of Winds" was large enough for actual airplanes.

When it comes to handsignals (and colonialism) rock always beats scissors.

The discovery site of the "Capitalsaurus," the official dinosaur of Washington, D.C.

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

Go take a picture with the inventor of the daguerreotype photographic process.

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

An unassuming, powerful monument north of the U.S. Capitol bears witness to the resilience of Japanese Americans during a time of grave injustice.

The unique traffic pattern named for an influential urban planner is also known as the Pedestrian Scramble.

The only Civil War battle in Washington D.C. took place near this highest natural point in the city.

Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

Perhaps the most scandalous statue of America's first president.

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

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

Largest Roman Catholic church in North America.

The oldest continuously operating fish market in the United States.

There’s a hidden military meme engraved on the World War II Memorial.

The national park was once a plantation estate.

This stunning blue and gold room changed cities twice before becoming part of the Smithsonian.

A painfully obvious spy house sits right across the street from the Russian Embassy.

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

Home to items never before seen by the public.

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