Stone memorial that's said to predict the death of the pope and the site of the Cadaver Synod.

The ruins of an abbey believed to have been founded by Charlemagne in the 9th century.

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

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

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.

This hermitage celebrates the legend of Emperor Constantine's healing from leprosy.

An 18th-century post box used to alert the church of sick and ailing foreign pilgrims.

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.

The ruins of the largest gladiatorial school in Rome are largely hidden under modern streets.

St. Francesca Romana, patron saint of drivers, resides in the church she founded.

A magnificent waterfall is also home to the remains of a Roman hydraulic engineering system.

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

2300-year-old Roman road connecting the empire.

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

This delightful little museum is dedicated to only one thing: pasta.

Once known for its horse-powered knife sharpening, this 200-year-old shop offers an array of blades and hard-to-find culinary tools.

A tree that defies gravity grows in an ancient ruin.

A quiet Sicilian village is home to a cafe that had an important role in "The Godfather."

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

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

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.