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

This isn't your average roadway—it's actually a National Park and a transportation pioneer.

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

A bas relief commemorates the "Nuns of the Battlefield" who cared for soldiers on both sides of the conflict.

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

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

A celebrity from the late Cretaceous period.

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

The beloved statue at the National Academy of Sciences is oh so inviting to sit on.

An extensive, if one-sided, history of U.S. law enforcement's war on drugs.

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

The most accurate timepiece in the world.

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

A tiny piece of the Moon is embedded in this stained glass masterpiece.

The sci-fi villain is a little-known inhabitant of the U.S. capital's largest cathedral.

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

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

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

This pun was simply waiting to come to life, and one defense contractor made it so.

At Washington's Dulles Airport is a satellite museum (no pun intended) with three quarters of a million square feet of aircraft history.

Exact replica of the ancient monument, but much, much lighter.

The largest permanent Monopoly board makes one of the longest games even bigger.

An extensive collection of ancient Egyptian artifacts and mummies.