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.

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

Home to items never before seen by the public.

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

A heroic pigeon that, through a barrage of gunfire, delivered a message that saved over 100 lives in World War I.

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

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

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

There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

This mysterious structure by the Washington Monument is a flood barrier designed to protect the White House against rising waters.

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

An overlooked memorial honoring the local Washington residents who died in World War I.

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