100 year tradition of fist fights, marked by marble footsteps.

Geothermal waterfalls in Tuscany.

This 16th-century monastery has been turned into a surrealist architecture compound.

Host to the annual Festival of the Snakes.

Water and windows define this defensive Italian well.

This picturesque Umbrian city has a subterranean side that has long remained hidden.

This quaint Italian town keeps losing ground as the sides of its plateau slowly erode.

This immaculate and historic water garden culminates in a massive stone dining table with an inset fountain for chilling the wine of the Cardinal's guests.

Ruins of a 10th century church tucked away deep in a botanical garden.

The remains of a town so thoroughly destroyed by French forces that the citizens simply left.

Medieval town turned hippie commune, once home to the secret foreskin of Jesus Christ.

Hidden beneath the famous St. Peter's Basilica is a veritable city of the dead that may hold the remains of St. Peter himself.

This ritzy Italian market is built around a statue of an unforgiven heretic who was burned for his belief in an endless universe.

One of several skulls claiming to belong to the beheaded St. John the Baptist is on display at this Roman church.

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

The underground sanctuary of a mysterious ancient cult.

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

The engineering wonder and pleasure dome of a much-maligned emperor still holds undiscovered secrets.

This historic recreationist school churns out warriors that may very well have had a fighting chance in Rome's pits of the day.

One of the last realized projects of an influential, self-taught, French Modernist architect Jacques Couëlle.

The only remaining collection of flayed figures made by French "madman" Honoré Fragonard.

This crumbling, graffiti-covered mansion sits tantalizingly within reach of the proletariat who frequent a public park.

The mummified heart of Louis XVII, the lost dauphin of the French Revolution.

Abandoned railway line circling the city of Paris.