River pirates, murderous bandits, and serial killers used this Illinois cave as their debauched hideout.

A geological mystery on Camelback Mountain.

Gambling, boozing, and yodeling animals cover the walls of this dive bar cum natural history museum.

143 feet of leaping muskie whose mouth can be used as a wedding venue.

This titanic oil company sign is a reminder of the Americana boom of the 1970s and also its commoditization.

What was once a presidential estate is now an exotic menagerie and home to the Budweiser Clydesdales.

A mythical bird etched into the face of a rock doubles as the mascot for a nearby school.

The only surviving prototype of Buckminster Fuller's revolutionary car.

Once one of the world's great cities, Cahokia was a place of religious worship, trade and mass human sacrifice before being mysteriously abandoned.

Less a museum than a bizarre fantasy world created by artists and engineers.

A floating museum that was sunk by a flood and left to rot in the tides.

Once an ambitious nature spa, these forest ruins now provide a serene monument to failure.

Erosion and time have created a naturally-formed water park.

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

The only natural lake in the world that drains into both the Atlantic and Pacific Oceans.

One of nature's most well-scheduled phenomenons resides in Wyoming's Yellowstone National Park.

The world's first nuclear power plant is open to visitors looking to role-play a meltdown.

Home to the deepest rift anywhere on Earth.