This 6th-century church has the largest and best-preserved collection of Byzantine mosaics outside Constantinople.

Featuring the last fully walkable parapet walkway in Europe.

The intricate geometry inside this Baroque-style dome was designed to create "terror of the human soul."

The “Sistine Chapel” of the Middle Ages merges 11th-century science and religion in wondrous hues.

This scenic fortress dates back at least 2,400 years to the time of Magna Graecia.

This triumphal 16th-century arched gateway leads to the oldest street in Palermo.

This ancient Roman arch misled treasure hunters for centuries.

The pristine waters crossing this forest form a hidden waterfall among the dense vegetation.

Gorgeous views of Italian mountains and valleys form the backdrop of this unique open-air theater.

This serene, turquoise lake in an extraordinary nature reserve showcases a rare natural phenomenon.

This church carved into the rocks is full of enchanting stone statues.

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

Explore the quarry where the marble was sourced for Michaelangelo's David.

Largest necropolis in the Mediterranean.

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

Haunting graffiti left by prisoners of the Spanish Inquisition.

Water and windows define this defensive Italian well.

A dreamlike medieval church dug into the tuff rock, with unusual carvings and possible traces of the Templar knights.

The sunlight passing through the opening of this huge cave system creates a magical effect.

An exclusive waiting room built for the royal family in the 1920s is hidden in Milan’s central station.

Remnants of a 4th-century church with vivid medieval frescoes and ancient sarcophagi hide beneath this old basilica.

A fascinating assortment of cave dwellings, medieval ruins, and sarcophagi are being devoured by the forest.

Naturally preserved bodies are eerily staged throughout the crypt in varying poses.

Da Vinci's equestrian statue, 500 years in the making.