The perfectly preserved underground rooms where Churchill plotted the war against Germany.

The winding route passes through an enclosed alleyway, two tunnels, and leads to the White House basement.

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

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 museum cafe showcases Native American dishes and indigenous ingredients from across the Western Hemisphere.

While most wind tunnels test scale models, the "Cave of Winds" was large enough for actual airplanes.

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

The "lovely red Vega" of the legendary record-settling pilot.

One of the most influential presidents in U.S. history wanted only this plain, elegant monument as his lasting memorial.

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

A computer bug so primitive it was an actual insect.

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

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.

On the Fourth of July this area will transform into a Pompeii-like storm of falling embers and ash.

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

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

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

Heralded as the world's first theater, these ruins are often overlooked as they reside in the shadows of the Acropolis.

Legend says this sacred tree was a gift from goddess Athena.

A minotaur, a labyrinth, and a dubious restoration pull in visitors from around the world.

1,500 Commonwealth servicemen of World War II are buried or commemorated in this cemetery.

The oldest olive tree in Greece has been bearing fruit for at least 2,000 years.

A contemporary art installation housed within a Gothic cathedral.