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

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

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

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

A hospital where antique dolls are given new life.

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

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

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

Jesus' footprints and the first catacombs in the world.

A fairy tale castle in modern Rome.

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.

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

The final resting place of the poets Shelley and Keats.

2300-year-old Roman road connecting the empire.

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

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

At the crypt of St. Mary of Eulogies and the Dead you are left alone to ponder mortality among piles of skulls.

The underground sanctuary of a mysterious ancient cult.

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

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

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

Architectureal fantasy quarter of Rome.

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