This ancient Roman prison is decorated with an upside-down cross not as blasphemy but as saintly tribute.

St. Francesca Romana, patron saint of drivers, resides in the church she founded.

The underground sanctuary of a mysterious ancient cult.

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

Jesus' footprints and the first catacombs in the world.

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

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.

A fairy tale castle in modern Rome.

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

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

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.

The final resting place of the poets Shelley and Keats.

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

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

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.

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

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

The Vatican's secret porn-festooned bathroom was painted in erotic murals by one of the greatest artists of the Renaissance.

Architectureal fantasy quarter of Rome.

An Italian ghost town that fought obscurity, until a mysterious illness brought it to its knees.

Largest necropolis in the Mediterranean.

Gigantic mosaic sculptures of the figures on Tarot cards fill this colorful Tuscan garden.