Enormous underground chamber built to detect 'ghost particles' of the universe.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

A petite white lighthouse perched on the ancient core of Stromboli Volcano.

The ancient settlement attracts tourists from all over looking to learn about the Chinese vision of the afterlife.

One of the tallest buildings in Iceland, and perhaps, the most visually impressive.

Constantly maintained, this organ is playing a six-century long composition by John Cage.

A particularly creepy abandoned hospital that sparks interest for lovers of the supernatural.

The feral felines of Roosevelt Island have a small army of allies and an abandoned hospital all to themselves.

On Japan's Tashirojima Island, cats are king.

This beautiful "lagoon" is actually a toxic soup filled with cars, carcasses, and trash. When warnings couldn't stop people from going for a dip, the town dyed it black.

Rising from the sea like a stone monster.

A fantastic castle rumored to be the birthplace of King Arthur.

The unusual private collection of modern-day renaissance man George Musgrave.

The largest of London's subterranean rivers and once a mad, bad center of London life.

The remains of the great moral philosopher reside in a university in London.

Winding paths and ramshackle mausoleums in the oldest "park cemetery" in London.

Europe's largest prehistoric mound – burial site of a legendary king?

The loneliest island in New York.

This ancient village and its adjoining cemetery have a beautiful history of death and remembrance.

An endless sea of white conical domes.

The largest catacomb system in the world.

An archive of nearly every day of Buckminster Fuller's life.

This lab's maddening silence is good for business but bad for sanity.

Below a historic English market town lies a secret underground city complete with kitchens, laundries, storerooms, and an underground lake.