A geological oddity formed by two rivers carving out a mass of limestone on both sides.

Like Stonehenge, but with boats and oodles more charm.

Curious cave that stays a cool 56 degrees all year long.

The history of funerals and funerary customs.

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

Taxidermy, Cigar Store Indians, A Model of a New York Tenement and Delicious Draft Root Beer.

In the loving memory of a tragically deceased role-player this Illinois park is decked out with both dungeons and dragons.

Giant granite rocks standing end-to-end like a train of circus elephants.

400 million-year old limestone caverns nestled in the Ozarks served as shelter and a hideout for cultures throughout North American history.

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

An extensive collection of fine art devoted to man's best friend.

This spot in St. Louis, marked with a simple sign, has seen more pro baseball than just about anywhere else in the world.

Man-made geyser that rises to the exact height of the Gateway Arch.

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

A big museum full of little worlds.