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

The once forbidden "secret cabinet" of erotic art from excavations of Pompeii and Herculaneum.

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

Abandoned medieval hill town.

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 Italian hillside ghost town.

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.

Venice's "Island of the Mad."

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

The middle finger of modernity.

Stalactites and stalagmites in a beautifully lit cave.

Thousands of well-dressed mummies below a monastery.

Pompeii's less famous neighbor is still revealing her secrets.

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

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

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

According to the local folklore, the myriad colors of this lake are the result of a lovelorn wizard's blunder.

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

The location of the last witch trials of Italy, known as "The Salem of Europe."

Medieval torture techniques with a modern conscience.

Geothermal waterfalls in Tuscany.

The underground sanctuary of a mysterious ancient cult.