The doodles of a genius line the walls of a secret room under the Medici Chapel, where they were hidden for nearly 500 years.

The middle finger of modernity.

The underground sanctuary of a mysterious ancient cult.

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

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

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

Architectureal fantasy quarter of Rome.

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

A 16th-century horror show built in a lovely Italian garden.

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

One of the most important yet well-hidden museums dedicated to the history of medicine.

Also known as the Square Colosseum, this building is a prime example of fascist-era rationalist architecture.

The spot where the fascist dictator made some of his most famous speeches including declaring war on Britain and France.

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

Believed to be the remains of the lost Temple of Minerva, this nymphaeum has been known by its misnomer to this day.

In the early Roman Empire, people deemed traitors and criminals were tossed to their deaths from this rock.

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

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

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

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

Ancient ruins hidden underneath a modern luxury hotel.

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

Inside this McDonald's you can dine on your Big Mac and fries next to a 2,500-year-old Roman wall.

A fortified medieval basilica on the Caelian Hill preserves extraordinary frescoes and one of Rome's most beautiful hidden cloisters.