A Nesting Doll of Churches.

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

Filled with goldfish swimming in a shallow pool of sea water, this ancient crypt is more wishing well than burial site.

Pilgrimage site for star-crossed lovers.

This former Roman Catholic Church still contains the embalmed hearts and organs of 22 popes.

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

Skulls from the plague of 1656 and World War II bombings are united by a cult dedicated to caring for the ancient dead.

This beautiful park on the outskirts of Rome protects the ruins of two colossal ancient aqueducts.

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

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

A labyrinth of ancient tunnels hidden below the city holds the ruins of 2,500 years of history.

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

A fairy tale castle in modern Rome.

Jesus' footprints and the first catacombs in the world.

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

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

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

The final resting place of the poets Shelley and Keats.

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

2300-year-old Roman road connecting the empire.

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

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

The underground sanctuary of a mysterious ancient cult.

Rome's semi-secret peephole vista is also a former Crusader stronghold.