This gold-winged spire celebrates the first true flight around the world.

The tech giant built three enormous glass orbs in Seattle so employees could work inside a rainforest greenhouse.

Though strikingly beautiful, Seattle's other railway station is now largely forgotten.

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.

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

One critic described it as "middle Mussolini, early Ramses, and late Neiman-Marcus." Another called it an architectural "natural disaster."

Disks are rolled out onto the south lawn to absorb the impact of Marine One's wheels like giant coffee coasters.

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

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

A muscular Art Deco monument represents the struggle between regulators and unbridled markets.

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

A gorgeous mural outside a beloved D.C. restaurant pays homage to famous Black Americans.

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

A little marble compass above George Washington's (empty) tomb in the Capitol marks where D.C.'s four quadrants intersect.

Where the U.S. government kept its actual treasure, before Fort Knox.

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

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

The house where John Wilkes Booth conspired with his co-conspirators.

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

A former hospital is now home to a pizza parlor and maybe a few ghosts.

A local landmark with generations of spraypainted messages, and more being added each day.

Pensacola's UFO home has withstood many hurricanes—just as the experimental 1960s design intended.

This now-deactivated naval base defended the Florida coast for centuries.

One of the only Florida forts to remain in the hands of the Union all through the Civil War still stands as a historic stronghold.