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

17th century streets hidden under Edinburgh were once a breeding ground for the black death.

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

The popularity of Sherlock Holmes led to the creation of his fictional address, turning the orderly London street numbers askew.

Famously misunderstood wonder of the ancient world

This collection of illusory paraphernalia has been culled from the history of London's premier magician's club.

This dramatic landscape hidden on the Isle of Skye looks as though you've stepped into the magical realm.

The sign at the garden gate reads: "These Plants Can Kill."

This churchyard arbor is surrounded by hundreds of gravestones placed there by author Thomas Hardy.

This shop and gallery is a modern-day cabinet of curiosities, unassumingly positioned along an urban thoroughfare.

These fantastically named natural pools look like something out of a Scottish myth.

The mysterious, fantastical woodland inspiration for "The Lord of the Rings."

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

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.

An ancient artistic garden parlor full of hidden water wonders.

This overgrown mountain village has been abandoned for nearly a century.

A haunting collection of sunken wooden barges litters this Italian river bend.

Stare out over the lagoon and beyond from this 10th-century campanile on the island where the city of Venice began.

Built to be the ideal penitentiary, this abandoned panopticon saw several revolts and even a prisoners' coup.

Small on the outside, big on the inside, this church is an astonishing act of visual deception.

Long-abandoned art nouveau baths beneath Milan's Piazza Oberdan.

Nestled in the heart of Milan is a real wunderkammer of morbid curiosities.

Vast network of air raid tunnels beneath Lombardy's capital.

Remnants of cone-shaped fascist bomb shelters in Milan.