The remnants of an early automobile route across shifting sand dunes can still be found in the deserts of Southern California.

Explore the largest pure gypsum deposit in the world, and go dune sledding while you're at it.

A sculpture made of 10 Cadillacs as a monument to the "Golden Age" of the American automobile.

WWII-era bunkers are hidden under the beaches of this picturesque park, which is still scattered with wartime watchtowers. .

Hidden deep within New Jersey Pine Barrens is a massive graffiti wonderland.

This rare triple-jurisdiction drawbridge passes through Virginia, Maryland, and Washington, D.C.

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

The remains of a historic plantation nestled in between a parking lot and the rental car return at Reagan National Airport.

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

A traveling postal dog covered 48 states and more than 140,000 miles, and he lives on as taxidermy, patched up with a rabbit's foot and a pig's ear.

Fittingly, America's museum of architecture is itself a magnificently designed old building.

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

This statue of the "father of television" stands prominently in the United States Capitol.

Rumor has it the uncarved lump behind the three famous suffragists is reserved for the first woman president.

Corn-inthian columns with a uniquely American take on neoclassical architecture.

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 remains of Martha, the last known passenger pigeon, serve as a tool to educate about conservation.

The 28,000-year-old specimen is remarkably intact.

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

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

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

This taxidermy horse was a Civil War hero.

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

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