This titanic steel chain linking two buildings was installed without permission but instantly beloved.

After a short-lived attempt to bring America in line with the rest of the world, this road was left in metric.

America's only nuclear missile silo open to the public.

Rare videos and memorabilia await visitors inside this unique store.

Decades of discarded bottle caps line this alleyway, a fixture of Texas A&M.

255 feet of suds, scrubbers, and blow dryers.

An ivy-covered arch bridge dedicated to Tejano music singer and legend Rosita Fernandez.

A taste of Middle Earth, in the middle of the Bayou City.

Housed in a century-old building, this museum's dedicated not just to soft drinks, but to the free enterprise system.

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

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

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

The remains of a historic plantation nestled in between a parking lot and the rental car return at Reagan National Airport.

The tunnel under the Capitol Building where Congress takes out its trash.

The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

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.

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

The oldest building in the District of Columbia was preserved because of a mistaken connection to George Washington.

A historic ruin just 20 feet away from a busy highway onramp.

An atomic bomb-proof strongbox protects the U.S. Constitution from terrorists and thieves.

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

Remains of the artificial harbours invented for the Allied invasion of Normandy can still be seen at sea.

Miles of man-made caves and tunnels are currently used for cultivating mushrooms.