This small, ancient Roman temple was once a church dedicated to the patron saint of penitents.

This curious, round temple is the oldest still-standing marble building in Rome.

This one-of-a-kind Roman arch is not actually dedicated to the god Janus.

The "Greatest Sewer" of ancient Rome is one of the oldest sewer systems in the world, and is still in use.

The only remaining arch of the oldest stone bridge in Rome stands in the middle of the Tiber.

This is the oldest Roman-made bridge in the city still existing in its original state.

A massive marble foot is tucked away in a small alley near the Pantheon.

A statue representing a lost Roman profession that was vandalized for centuries.

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

Historic fortifications form the boundary of Vatican City, but it’s not entirely surrounded by walls.

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

Breathtaking and huge 430 year old maps of Italy.

This gallery commissioned by Cardinal Spada is known for its magnificent optical illusion.

Brass cobblestones mark the places where individual Holocaust victims were taken from their homes.

This statue is the only female representation of Rome's "talking statues."

These hut foundations are believed to be the residence of Romulus, founder 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.

An ancient Roman temple first dedicated to an emperor's wife is now a church.

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

The last moments of the ill-fated Pompeiians, frozen forever in plaster.

The walls and streets of the ancient city are peppered with penises.

Erotic art covers the walls of the largest ancient pleasure palace.

Ancient snack bar of the Roman Empire re-opened.

Before it was buried by volcanic ash, this fast-food restaurant fed the hungry hordes of ancient Rome.