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

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

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

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

Jesus' footprints and the first catacombs in the world.

A hospital where antique dolls are given new life.

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

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

The final resting place of the poets Shelley and Keats.

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

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.

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

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

Hundreds of lucky felines haunt the ruins where Caesar was murdered.