Made of giant chains and hung with shackles, this iron cross honors those unknowns who perished under American slavery.

This bar named after the world's first mixed cocktail was home to one of New Orleans' most notorious politicians.

The beautiful, fruit-covered facade hints at this building's former life.

Formerly known as National D-Day Museum, this collection commemorates the battles of Normandy and WWII.

This historic "City of the Dead" lies prominently in the center of New Orleans' famous Garden District.

This is probably not the Target you're looking for.

This quirky outpost and gallery inside a former church is an unexpected trove of handcrafted art.

This old abandoned sign flickers to announce a motel that isn't even there.

Twenty-seven massive radio antennas on the high plains of New Mexico search for life on other planets.

A cave's rare beauty held a cavernous secret hidden underground.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

A prison-like structure guards the remains of a notorious Old West outlaw.

In the middle of an extremely unforgiving and desolate high desert is the most secret military facility in the world.

Eons ago, a rushing lava river formed this pristine passage through solid rock.

Most-visited and most-photographed slot canyon in the American Southwest.

This secluded aqua waterfall in the Grand Canyon is the perfect swimming hole, and the Havasupai tribe's fiercely protected natural wonder.

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

Along the old Route 66 is an abandoned trading post made from old telephone poles, built by a former circus clown.

This Arizona observatory is famous for investigations into Martian life, and as the place humans first spotted Pluto.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

The story of Two Guns, Arizona could easily be described as a Shakespearian tragedy on Route 66.

A stealthy Apache hideaway that became the haunting site of a mass grave.

Leave it to Key West to drop a real-live drag queen instead of a ball to mark the arrival of the New Year.

Stay in a room with a view... of the bottom of the ocean.