This Hungarian castle was built out of cardboard and wood until it proved so popular that it got upgraded to stone.

There are plenty of wonderful panoramic vistas in Edinburgh, but not many are hidden smack in the middle of the Old Town.

Near the former site of numerous witch burnings, this lavish Edinburgh mainstay pays homage to Scotland's brutal history.

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

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

Drink wine handed out through a window as part of an age-old tradition.

Over 50 exquisite hand-painted Renaissance maps decorate a Medici storage room.

A large grotto built in the 16th century amidst Florence's famous Boboli gardens.

The doodles of a genius line the walls of a secret room under the Medici Chapel, where they were hidden for nearly 500 years.

Only museum in the world devoted to bookbinding and book arts holds a permanent collection representing five centuries.

Scale model of St. Peter's Cathedral (Rome) in the middle of a small Dutch town.

The oldest stone house in Paris was built by its most famous alchemist.

This iconic L.A. bookshop is housed in an abandoned bank—both symbolic and chic.

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

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.

A remote candy-striped mountain in the Peruvian Andes straight out of the pages of Dr. Seuss.

Hot springs monkey spa in the middle of Hell's Valley.

The inspiration for H.P. Lovecraft's horror stories and Batman's Arkham Asylum is now a condominium complex.

Where Mary Shelley’s "Frankenstein" and John William Polidori's "The Vampyre" were born.

These rows of World War II-era bunkers were the scene of some of the infamous Mothman sightings.

A small storefront museum explores the history and myth of West Virginia's famous urban legend.

A peculiar mansion built by the troubled heir to the Winchester Rifle Company fortune.

The only structure left with direct ties to the Salem witchcraft trials of 1692.

Claiming to be the oldest hat store in the world, this historic haberdashery had a hand (and a head) in the creation of the Bowler.