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

Go inside to really appreciate this 500-year-old technological masterpiece.

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

A collection of objects supposedly singed by the hands of souls in purgatory.

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.

Jesus' footprints and the first catacombs in the world.

This sword isn't waiting for a king to pull it out. It was placed there by a saint.

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

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

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

Natural cathedral designed by Italian artist Giuliano Mauri.

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

Abandoned medieval hill town.

An Italian hillside ghost town.

The final resting place of the poets Shelley and Keats.

The largest and most famous wax anatomical collection anywhere in the world.

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

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

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

2300-year-old Roman road connecting the empire.

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

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

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

As can be expected from a centuries old church built in a canal city, the undercroft of this house of worship is beautifully flooded.