This noble mash-up in eastern Luxembourg is part Medieval, part Renaissance, all castle.

Once the local rulers had gone these enchanting ruins housed common folk in an almost real life fairy tale.

Germany's longest suspension rope bridge.

Now overgrown, these anti-tank barriers from World War II are sometimes called "dragon's teeth."

A top-secret bunker now turned museum, is an eerie look at what life would have looked like in the event of nuclear war.

An extraordinary "City of Caves" carved from solid stone.

This ultra-modern burial building would have stacked the dead like a giant filing cabinet.

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

An eerie, derelict amusement park in Berlin.

A diverse collection of wax, bone, papier-maché and mummified relics.

The mummified relic of St. Catherine sits forever on a golden throne.

Machismo turned on its head: the lady's hand goes to the dude with the bigger brain.

France's most famous cemetery, with some of its most curious tombs.

The tunnel's elegant proportions keep you snug with no claustrophobia freak-out.

This artificial cave looks like something out of a fairytale.

A giant gun barrel in Barbados that once hoped to shoot outer space with science.

Deadliest lake in the world suffocated over 1,746 people in one night.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

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

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

Terrifying derelict military hospital once housed a recuperating Hitler.

Centuries-old bridges grown from tangled roots.

An organ located deep within a cave, whose "pipes" are the geological features of the cave itself.

The remains of diamond fever taken over by the desert.