This stunning blue and gold room changed cities twice before becoming part of the Smithsonian.

The most decorated dog of World War I is preserved in the Smithsonian.

A heroic pigeon that, through a barrage of gunfire, delivered a message that saved over 100 lives in World War I.

The oldest continuously operating fish market in the United States.

Look closely and you’ll notice that the color changes a third of the way up the tower.

The first purpose-built art gallery in the United States is once again open as a center of craft arts.

A former major munitions plant that has been converted into a sprawling art space.

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

Long buried under the 20th-century landscape, this lift lock of the Alexandria Canal is the lone remnant of an ambitious early American transportation project.

A superbly preserved example of Georgian residential architecture that was once home to one of the founders of Alexandria, Virginia.

The final resting place of an unidentified revolutionary soldier sits behind a Virginia church.

A piece of the Ludendorff Bridge, also known as Remagan Bridge, calls this military base home.

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

A massive, majestic mammal watches over pedestrians from his perch atop a former B.P.O.E. lodge.

This colonial tavern played host to George Washington, Thomas Jefferson, and other famous early Americans.

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

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

This lovely picnic spot featuring thunderous jet landings is an aircraft spotter’s dream.

The word "Watergate" will forever be associated with the infamous scandal in 1972, but this fountain is famous in its own right.

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

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

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

This seemingly out-of-place gas station by the Watergate hotel was once described as the most expensive gas station in the world.

Before Nixon, "watergate" meant canals.