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

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

The unique traffic pattern named for an influential urban planner is also known as the Pedestrian Scramble.

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

Members of Congress have traveled between the buildings on Capitol Hill for a century hidden from tourists, press, and storm clouds.

Perhaps the most scandalous statue of America's first president.

The oldest continuously operating fish market in the United States.

It was once the base for a series of domestic terror attacks.

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

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

This grand gothic brewery has been pumping out suds for over a hundred years.

Nuclear reactor created the plutonium used on Nagasaki.

A wall of chewing gum moonlights as collective art.

A walk through the historic city center, under the streets of Seattle.

The romance of early commercial flight still fills this Art Deco destination.

At Washington's Dulles Airport is a satellite museum (no pun intended) with three quarters of a million square feet of aircraft history.

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

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

A house carved into a rock in the 1940s.

A 90-foot-tall psychedelic "tree" on the side of the highway has baffled passersby for decades.

The largest wildlife crossing in Utah allows local fauna to safely traverse the six-lane Interstate 80 at Parleys Canyon.

The fifth-longest natural arch in the world, and the longest outside China.

The marker offers a rare chance to be in four U.S. states at once, though there's some controversy over its geographic accuracy.

Come for the speed, leave in love with the desert.