Run by a eugenics advocate, this aging institution conducted secret radiation experiments sponsored by Quaker Oats.

A museum devoted to bringing to light forgotten or neglected histories through exhibitions, education and public programming.

A theme park that suffered massive flooding during Katrina was abandoned, and now proves irresistible to trespassing explorers.

A fiery crater has been burning in the Karakum Desert since 1971.

The mysterious, fantastical woodland inspiration for "The Lord of the Rings."

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.

An emerald-green grotto just a short trip from Austin.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

A peculiar mansion built by the troubled heir to the Winchester Rifle Company fortune.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

Palatial mansion estate used in films including "Flowers in the Attic" and "The Witches of Eastwick."

An eccentric inventor's castle home with its own indoor weather system.

A true treehouse near Hawai'i Volcanoes National Park.

These ancient sacred grounds granted amnesty to those who managed to reach them.

Hide from the tourist hordes in these relatively unknown, and unguarded lava caves.

The remains of a 19th century spring, and the site of an infamous unsolved murder.

Beneath the mossy overgrowth covering this once-sprawling campus lies decades of history and the secrets that come with it.

Sparkling, calcite-covered skeletons of children who may have been sacrificed to appease an angry god.

Better known as the "Body Farm," this unique research facility has been studying how human bodies break down since the 1980s.

This attraction was abandoned after the Chernobyl disaster.

A stratovolcano located in the south of Iceland, with a long history of charted activity and a rich mythology attached.

Steaming blood-red hot spring from hell.

The fairy tale castle of the "fairy-tale king."

Once the most densely populated place in the world, this island is now a ghost town.