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.

Before Metro, Washington had a robust streetcar network—and you see the remains of this infrastructure if you know where to look.

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

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

"Congress may voluntarily remain in session throughout the summer, in order that our Congressmen may be protected from the intolerable discomforts and dangers of the ordinary outdoor weather!”

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

The fountains of the U.S. Navy Memorial are annually salted with water from the Seven Seas as part of a nautical ritual.

A tiny monument to the unsuccessful attempt by Thomas Jefferson to place the prime meridian in Washington.

A historic arena where the Beatles played their first concert in the U.S.

This robust fence in front of a historic Georgetown home is likely made from hundreds of recycled Revolutionary War firearms.

Architecture lovers won’t stop touching the National Gallery's 19.5 degree marble prow.

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

One of the largest artillery pieces in the world sits in a Washington D.C. parking lot.

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

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

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

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

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

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

The most accurate timepiece in the world.

The oldest continuously operating fish market in the United States.

The national park was once a plantation estate.

It was once the base for a series of domestic terror attacks.