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

Please don’t anchor your boat onto the Department of Defense’s underwater data cables.

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

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

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

The grand marble structure next to the White House is Andrew Carnegie's temple to Pan-American diplomacy.

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

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

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

Born a slave on the Arlington estate, Parks dug the first graves at Arlington National Cemetery, and was buried there, too.

The rogue roots are gradually consuming some of the historic marble grave markers.

The naval commander’s proudest moment in battle is memorialized in this unique tomb at Arlington Cemetery.

A gift from Scotland to the United States in memory of the 270 lives lost when Pan Am Flight 103 exploded over Lockerbie due to a terrorist bombing.

In what is rumored to be an intentional act of spite, this memorial almost completely obscures the nearby grave of a senior officer.

Though his role as the inventor of baseball may be up for debate, fans still festoon Doubleday's grave with baseballs.

Soldiers were buried next to Lee's house in the center of Arlington Cemetery to dissuade the general from reclaiming his property after the war.

The controversial urban planner who designed Washington, D.C., was buried in Maryland, and can presently be found in Virginia.

Recorded as the first person buried in Arlington Cemetery.

An oft-overlooked, magically musical monolith that stands majestically between Arlington Cemetery and the Iwo Jima Memorial.

This site is believed to be connected to the oldest house in Arlington County.

This church built atop a gas station promises to "equip you for the next stage in your life’s journey."

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

The narrowest house in America is seven feet of pure spite.

This small pedestal marks the spot of the first lot of land sold in Alexandria, Virginia in 1749.