Ancient man-made caves underneath small town Belgium.

This ghost town in Belgium will lose its street art when it ceases to exist.

This former Nazi castle was built as a school to train what would have been the future of the Third Reich.

Sacked by Vikings, blessed by William the Conqueror, dealt a fatal blow during the French Revolution—these ruins have seen it all.

In an area where the remnants of WWI are discovered on a regular basis this preserved frontline trench may be the most amazing.

This amazingly preserved Gold Rush town is a historian's dream.

A smoke stack so large, the Washington Monument could fit inside!

A unique waterfall that some believe attracts the fairfolk.

A legendary rocking stone, returned to its clifftop perch.

Even France's favorite aquatic son Jacques Cousteau, couldn't get to the bottom of it.

Large Hadron Collider and the Birthplace of World Wide Web.

Berlin's old airport.

A state-of-the-art medical facility from the Imperial era is now a derelict ruin.

A museum dedicated to the history of a terrifying secret police is now held in their former headquarters.

Home to three historic ships from the age of Vikings.

Walk 2,300 feet above the ground on the "Troll's Tongue."

The last bastion of Roman presence north of the Alps looms over a German town.

This Dresden church was purposely rebuilt Protestant after being demolished in World War II.

Hitler's bleak vision of relaxation still stands as a mostly abandoned 10,000-room resort complex.

The NASA scientists behind Apollo 11 started out developing Nazi weapons at this abandoned German rocket factory.

Horrifically creative torture devices and shame punishments line the walls of this chilling museum.

Housed in an old church, this hunting museum holds a collection of mythical bird-rabbit creatures.

A centuries-old complex of hand-dug stone chambers has sheltered locals in times of trouble.

A strange rock formation with numerous legends trying to explain it.