Two very green residential towers cleaning the air in one of Europe's most polluted cities.

Romans built the world's tallest artificial waterfall in 271 BC.

This mosaic-lined medieval church was built by the world's first admiral and still holds mass in ancient Greek.

Every day is like Christmas on this street where the traditional Neapolitan nativity scene comes to life.

Brass cobblestones mark the places where individual Holocaust victims were taken from their homes.

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

More sculpture than building, this architecturally significant temple was built on the spot of Saint Peter's crucifixion.

Pilgrimage site for star-crossed lovers.

This ancient market is often referred to as the oldest shopping mall in the world.

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

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

These "anatomical machines" are only one of the many strange items in this Italian crypt.

This quaint Italian town keeps losing ground as the sides of its plateau slowly erode.

Dug as a secret royal escape route, the tunnel became a wartime bomb shelter and dumping ground for vintage cars.

An Italian hillside ghost town.

Crushed coral and crystals give the sand its signature coloration.

Five candy-colored villages on the Italian Riviera.

This shining multicolored metro station deep under Naples is said to be the most beautiful in Europe.

Pompeii's less famous neighbor is still revealing her secrets.

Geothermal waterfalls in Tuscany.

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

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

A forgotten "city of water" underneath the famous Trevi district.

The final resting place of the poets Shelley and Keats.