This Nazi ruin was the site where Hitler was almost blown up by a suitcase bomb.

These spooky and unusual stone formations create an underworldly landscape.

Over 3km of caverns and caves at the Switzerland-France border contain the largest underground river in Central Europe.

17th century streets hidden under Edinburgh were once a breeding ground for the black death.

This picturesque archeological site looks like it was pulled straight from a fantasy novel.

These fantastically named natural pools look like something out of a Scottish myth.

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

Harry Potter once visited this massive limestone cliff, which was carved by an ancient glacial river.

The world's largest prehistoric copper mine had 30,000 animal bones scattered throughout the maze of passageways.

A subterranean playground in an abandoned slate mine.

Mysteriously stacked storefront paths give this medieval British town an iconic style like none other.

Created hundreds of years ago, the magical follies and landscapes at this park were almost lost to time before being restored.

Three bridges straddle a stream, one stacked upon the other.

The largest known medieval map of the world.

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

This lovely little burbling creek is actually a deadly waterway that has dragged down everyone who ever set foot in it.

This ancient bridge made of stone slabs is said to be reserved for the devil to sunbathe.

The world's largest collection of witchcraft regalia.

A 200-year-old prison that now houses a peculiar crime museum.

A open air theatre built on a cliff by an eccentric British woman.

A island reachable by a causeway at low tide is possibly one of the earliest Western European locations to be identified in text.

This tangled English forest looks like something right out of a fairytale.

This former quarry is now a vibrant labyrinth of magical in situ sculptures.

This stream-carved gorge has inspired poets, hidden smugglers, and trained soldiers, all without losing its beauty.