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.

A battle between nature and architecture in the Cambodian jungle.

The ruins of this gorgeous clifftop castle look like something from a fantasy novel.

A 2000-year-old Roman amphitheater lies just below Guildhall Yard.

The oldest operating pharmacy in the world features 800-year-old recipes.

An Oxford museum where visitors can have tea with the Mad Hatter and climb through the wardrobe to a fantasy land.

A 18th century graveyard and its astonishing cortege of macabre iconography.

Tiny effigies of the victims of Edinburgh's famous Anatomy Murders.

This wildly-tiled artist's palace is a living and growing account of the creator's life, loves, and labors.

Ancient cliffs resembling a kilt on Scotland's second largest island emit an entrancing sound.

Spend the night in this formerly abandoned traditional Scottish village.

Japanese island famous for poison gas and fluffy bunnies.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

An ethereal glowing blue ocean cave in Croatia.

The final resting place to 300 Victorian-era pets hides inside the city park.

This eye-popping Icelandic crater lake is surrounded by red volcanic rock.

An incarceration museum on the spot of possibly the oldest prison in England.

This cemetery features modernist statues as strange as its name.

A historic London pub with prison cells in the cellar and a "spy room" on the second floor.

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

1,001 carved statues of the Buddhist God of Mercy, each with a unique face.

A 70-foot-deep ice cave formed by lava from Mt. Fuji on the edge of Japan's "Suicide Forest." 

This Buddhist temple is home to the graves of the Japanese national legends, the 47 Ronin.