Plaques on its facade commemorate the Tiber's most destructive deluges.

This private skyway is filled with art and was expanded explicitly so that Hitler could appreciate a river.

Legend says this mysterious stone head belongs to a woman who was petrified by an alchemist.

This bustling Italian plaza is built on the ruins of an ancient Roman amphitheater.

A brutalist gem towering over the heart of Milan.

An unremarkable wooden wheel built into the side of one of Rome's oldest hospitals was part of a policy to reduce infant exposure.

A 15th-century monumental Latin inscription on this house celebrates Lorenzo Manilio's love for Rome.

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

The Pope’s secret escape route.

The remains of this 2nd-century Roman temple are incorporated into a modern building.

San Gennaro, the patron saint of Naples, greets pedestrians between these narrow city streets.

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

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

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

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

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

A monumental fountain in Rome features a large statue of Moses that has been criticized for centuries.

Architectural monsters are devouring this palace's every door and window.

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

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

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

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

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

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