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

More sculpture than building, this architecturally significant temple was built on the spot of Saint Peter's crucifixion.

This Roman arch marks the location of an ancient gate at one of the Seven Hills of Rome.

A mysterious chasm in the heart of the ancient Roman Forum, the Lacus Curtius was once believed to be a gateway to hell.

This delightful little museum is dedicated to only one thing: pasta.

Installed in an act of one-upsmanship, the annual sundial in this church is also a symbolic victory for the Gregorian calendar.

One of seven Jewish catacombs in Rome and one of only two open to the public.

The martyr's wax-enhanced skeletal remains lie preserved in a glass case in the Santa Maria della Vittoria in Rome.

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

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

Jesus' footprints and the first catacombs in the world.

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

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

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

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

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

The oldest stone house in Paris was built by its most famous alchemist.

Ever hear of the Milazzo Cage?

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