A roaring, awe-inspiring double cascade of icy water flows through woodland Oregon like something out of a Tolkien novel.

Staves, storm-calling, and of course, necropants.

Mother Nature outdoes herself with this stunningly beautiful set of caves carved into marble.

Hot springs monkey spa in the middle of Hell's Valley.

The inspiration for H.P. Lovecraft's horror stories and Batman's Arkham Asylum is now a condominium complex.

A massive underwater sinkhole made famous by Jacques Cousteau.

Dramatic river bend surrounds a natural red-rocked pedestal.

The hidden "ballroom" under a mansion lake was built by a criminal who ate a cyanide pill during his trial.

A toxic ghost town sitting atop a massive coal fire.

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

A crumbling hospital from the 1850s on Roosevelt Island.

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

Medicinal spa created with the discharge from a geothermal energy plant.

On the Oregon coast there is a natural hole that seems to be draining the sea.

An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

An exquisite tunnel of cascading flowers.

World's first "penitentiary," meant to be humane, drove men insane.

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

A huge musical instrument played by the ocean.

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

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.

The sign at the garden gate reads: "These Plants Can Kill."

A rocky Irish outcropping with a history of wealth, conflict, and ruin.