The world's longest known cave system.

Bigfoot prints, Feejee mermaids, and haunted dolls on display in a tiny North Carolina town.

Towering basalt columns, a creation of fire and ice.

These delicate buggers are some of the rarest fossils that have bubbled up from the Tar Pits.

Architectureal fantasy quarter of Rome.

Take a drunken tour inside the world's largest known geode.

Under a glass sidewalk lie the remains of some of Manhattan's oldest buildings.

A beautiful geyser under environmental threat.

The world's only international cryptozoology museum is host to an unrivaled collection of mysterious objects.

A trash dump made beautiful by nature's power.

Ninety feet off the valley floor is an ancient dwelling put under protection of the U.S. government by Teddy Roosevelt.

The intricate stonework of Machu Picchu serves as a testament to Incan engineers.

The site of the climactic scene from the classic horror film is now a historic landmark.

The seamy, underground secrets of Portland's criminal past.

Home of an evil witch famous within southern folklore.

The feral felines of Roosevelt Island have a small army of allies and an abandoned hospital all to themselves.

Stroll through a wonderland of stupendous moss-covered trees.

A beautiful Victorian-era cemetery, complete with a miniature village.

Paranormal experiences in this hotel's room 217 led Stephen King to write "The Shining."

This Boston medical museum features the skull of the famous medical case of Phineas Gage.

This whimsical Oz-themed park had a wonderful impact on the surrounding neighborhood.

A walk through the historic city center, under the streets of Seattle.

A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

A bizarre house filled with an astounding array of collections.