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

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

The innocent intentions of this monument are somewhat lost in the sculpture's muscled imagery.

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

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

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

She stares out across six lanes of traffic, clutching a musket and infant with determination.

The United States Capitol's former columns still stand.

Once the supplier for noteworthy projects like the National Cathedral, this old brickworks now lies abandoned.

A verdant 17th-century-style garden hidden along Edinburgh’s Royal Mile.

A garden oasis filled with flowers mentioned in the works of William Shakespeare.

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

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

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

This small plaza encourages people diagnosed with cancer to never give up hope.

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

The actual model from the original "Star Trek" series is now on display at the National Air and Space Museum.

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

A hidden gem on the lawn of the U.S. Capitol Building designed by landscape architect Frederick Law Olmsted.

Home to items never before seen by the public.

This one-room cabin where the young colonel slept during the French and Indian War.

America's first federal monument.

The graveyard holding the remains of George Washington's slaves was forgotten for nearly 200 years.

The tomb was guarded by soldiers from both sides of the war, and some left their initials carved in the brick.