A whimsical and twisted animatronic monster tour beneath the streets of Berlin.

An Irish church where an 800-year-old mummy is reaching out of his coffin as if to shake hands.

"The most colorful grottoes of the world.

Ancient man-made caves underneath small town Belgium.

Incredible labyrinth of man made caves.

One man's personal kunstkammer, museum and shop.

The prototype for all Nazi concentration camps.

Where beer lovers can literally immerse themselves in beer.

Hiding the longest subterranean river known in the world.

Standing stones found on a construction site are re-erected.

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

The bizarre visions of H.R. Giger, tucked away in a Swiss medieval city.

A breathtaking bridge that crosses a vast gorge over a river's torrents, and has a tale of a devil architect attached.

Caves famous for the dragon-slaying saint who lived there.

One of the world's most complex timepieces.

Statue of a decomposing prince that once held his heart in its hand.

These spooky and unusual stone formations create an underworldly landscape.

This Nazi-built amphitheater was constructed on a sacred mountain site used by various German cults.

An ancient monastery, a locked room, and a mysterious book heist.

At the crypt of St. Mary of Eulogies and the Dead you are left alone to ponder mortality among piles of skulls.

The remains of 40,000 humans, meticulously stacked in a tiny churchyard shed.

The mortal remains of an estimated 70,000 people lie in the basement of a monastery in Lima, Peru.

Mysterious painted skulls in Moravia.

5,000 skulls in memorial to those killed by the Khmer Rouge.