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

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

2300-year-old Roman road connecting the empire.

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

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.

Renaissance villa and gardens complete with a tormented colossus.

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

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