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

This apartment building designed by a notable Washington D.C. architect housed the Qing Dynasty's Legation.

A brass and marble scale model of the solar system embedded in the concrete.

A hidden passageway now marks the site of an assassination attempt on Ronald Reagan that some say broke a 140-year-old curse.

Also known as the Founding Church of Scientology.

A public art jibe at one of the United States’ oldest and longest-serving senators.

The oldest house in Washington, D.C. wasn't originally constructed in the nation's capital.

A terrace reminiscent of Rome's Spanish Steps is tucked away in a little park in Washington, D.C.

Behind an abandoned storefront is an example of pioneering 1930s gas station architecture.

A small park honors the legendary Ukrainian poet.

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

Surrounded by traditional homes, this Tolkien-esque dwelling stands out on a quiet street in suburban Maryland.

This lifelike sculpture of a policeman serves as a helpful reminder to watch out for crossing pedestrians.

This fort down the Potomac from Washington, D.C. was once the only defensive fort protecting the capital.

Built to defend Washington D.C. during the Civil War, this fort became a post-war nucleus for a thriving Black community.

This tiny, one-acre cemetery serves as a reminder of when the Civil War got close to the nation’s capitol.

This American Civil War-era fort still stands near the border between Washington, D.C. and Maryland.

Franciscan monks created a facsimile of the Holy Land for North Americans who couldn’t afford the trip overseas.

The only surviving prototype for Buckminster Fuller's house of the future.

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

Parking garage where Bob Woodward met Watergate source "Deep Throat."

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

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.

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