The most isolated mailbox in America lets desert travelers record their passing.

Appropriation-friendly collection of books, periodicals, and more.

The wreckage of a World War II bomber is hidden high in the Colorado wilderness.

This grave marks the final resting place of a legendary frontiersman... unless it doesn't.

Explore the dark underground corridors of this graffiti-covered former military fortification.

A cave interior in the shape of the ancient rhinoceros, created by lava cooling around its carcass.

The only known Futuro house in North Carolina sits along a stretch of desolate highway on the Outer Banks.  .

This punny mirror of another Wisconsin attraction is exactly what it sounds like.

This New England covered bridge is home to the tale of a jilted lover known to haunt the area.

The huge collection of paintings of the American West is one of Denver's best-kept secrets.

An American city stranded at the tip of a Canadian peninsula where strict adherence to the "49th parallel rule" became problematic.

"X" marks the spot of an echo chamber in the middle of a plaza.

This stone is a marker of one millionaire's personal vendetta against gravity.

This stone tower marks a lookout point over the historic Washington Crossing, and maybe some buried treasure.

This hidden stream beneath Indianapolis makes an appearance in the best-selling novel "Underground Airlines."

The graves of a Connecticut family thought to have been plagued by a vampire.

Eight rare Corvettes are swallowed up by a sinkhole in Kentucky's National Corvette Museum.

Erected in 1697 this Philadelphia bridge is the oldest surviving roadway bridge and perhaps the oldest stone bridge in the United States.

World's second largest particle accelerator, where nature reveals its secrets.

No one's quite sure why there's a metal megaphone bolted on two rocks in the middle of the Mojave Desert.

A castle built for love, and abandoned due to heartbreak.

A natural history wunderkammer in the middle of the desert.

Behold the rickety wooden glory of the world's oldest operating roller coaster.

The world's largest collection of the world's largest objects is in one small Illinois town.