Last remaining nuclear missile base in Ukraine.

Budapest's Communist-era statues, banished to the suburbs.

An architectural marvel that spans the Arda River, and has stories of a haunted past.

In a long-dry lake bed, these groups of massive stone pillars bear a striking resemblance to clumps of everyone's favorite fungi.

A giant portrait of an ancient king looms over the river.

17th century palace once a meeting place for politicians.

The Natural History Museum that time forgot.

The growing stones of Romania.

A stunning 18th century pharmacy and medieval chemist's collection.

Steaming blood-red hot spring from hell.

The world's toughest modern Christian pilgrimage leads directly to the gates of Hell.

Rebuilt remains of a temple to Roman god Mithras.

A historic London cemetery now serves as a nature park incorporating gravestones & memorial statues.

A collection dedicated to the treatment of disease, held in London's oldest hospital.

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

The biggest and deepest Cold War bunker open to the public can be found in southeast England.

The curios of pharmacist and collector Henry Wellcome.

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

A cave network located at the southernmost tip of mainland Greece was once believed to be an entrance to Hades.

A beautiful, dense forest in the shadow of Mount Fuji, with a tragic reputation.

Superstitious? Discover the witchy side of Mexico through its largest esoteric market.

A mysterious chasm in the heart of the ancient Roman Forum, the Lacus Curtius was once believed to be a gateway to hell.

Skyscraper powered by wind turbines attached between its towers.

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