A 30-acre garden inspired by the principles of modern physics.

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

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

The world's largest collection of witchcraft regalia.

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

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

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

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

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

A Trabant car, a kangaroo statue, and a plethora of plants take over this abandoned-factory-turned-bar.

This statue of a falling man commemorates a teenage martyr of the Hungarian Revolution.

Late at night, the bust of the "Dracula" actor was snuck onto the facade of this Budapest castle.

Sitting beneath an unremarkable residential building is a museum devoted to classic Pinball.

Possibly the world's largest hourglass only needs to be reset every New Year's Eve.

Museum dedicated to the terror regimes of Hungary.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

Once the home of a hermetic monk, this cave now houses a small church.

A series of caves under Castle Hill that once held the prisoner Vlad Tepes, better known as Count Dracula.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

A 19th century artistocrat's mansion, turned into a library, hidden in a modern library.

This Budapest bar allows drinkers to leave their mark on the walls, floor, and even ceiling.

Ancient pueblos built into the base of a natural canyon wall.

In this small Phoenix taxidermy emporium, you can find everything from a squid in a jar to a freeze-dried toad.

Vienna's diversity-themed traffic lights were inspired by the Eurovision Song Contest.