Sitting on an Italian hilltop is this surreal fortress built by the mad inventor of electrohomeopathy.

Geothermal waterfalls in Tuscany.

Stalactites and stalagmites in a beautifully lit cave.

Architectural monsters are devouring this palace's every door and window.

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

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

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

An alchemist's "magic door" stands in the middle of a Roman park.

Rome's semi-secret peephole vista is also a former Crusader stronghold.

Architectureal fantasy quarter of Rome.

A 16th-century horror show built in a lovely Italian garden.

This hidden Art Nouveau courtyard is an opulent feast for the eyes.

An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."