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

An ossuary built in 1210 to collect bones from the Ospedale Maggiore of Milan.

The last moments of the ill-fated Pompeiians, frozen forever in plaster.

Hidden in an Italian forest is a completely homemade amusement park that has taken a lifetime to create.

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

Venice's "Island of the Mad."

The skull of the patron saint of lovers lies in the Basilica di Santa Maria in Cosmedin—maybe.

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

Thousands of well-dressed mummies below a monastery.

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

Stalactites and stalagmites in a beautifully lit cave.

The underground sanctuary of a mysterious ancient cult.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

A submerged archeological park still holds the wonders of a Roman Sodom.

This Venice bookstore has resigned itself to constant flooding by keeping its books in bathtubs and boats.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

The yawning maw of this pagan visage is said to bite off the hands of liars.

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

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."