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

The once forbidden "secret cabinet" of erotic art from excavations of Pompeii and Herculaneum.

This hill made entirely of ancient Roman jars was simply a garbage dump to the people of the time.

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.

A treasure trove of Renaissance-era funerary art in a Roman church built on top of Nero's grave.

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

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

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

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

A Nesting Doll of Churches.

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

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

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

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

Monument to a brutal, ineffectual US bombing campaign and a sobering reminder of the human cost of the Vietnam War.