A dismembered holy head stares out from her beautiful reliquary at the St. Dominic Basilica.

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

Ancient snack bar of the Roman Empire re-opened.

The world's most active stratovolcano is almost always erupting.

Erotic art covers the walls of the largest ancient pleasure palace.

Medieval torture techniques with a modern conscience.

An ancient artistic garden parlor full of hidden water wonders.

This winding road through an Italian canyon may be the most scenic drive in the world.

This picturesque Umbrian city has a subterranean side that has long remained hidden.

Virgil's many-mouthed gateway to the underworld.

The underground sanctuary of a mysterious ancient cult.

This palatial spiral staircase was so unusual the name "snail" was given to the noble family who built it.

A Nesting Doll of Churches.

Pilgrimage site for star-crossed lovers.

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

Go inside to really appreciate this 500-year-old technological masterpiece.

Five candy-colored villages on the Italian Riviera.

The once forbidden "secret cabinet" of erotic art from excavations of Pompeii and Herculaneum.

Jesus' footprints and the first catacombs in the world.

An Italian hillside ghost town.

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

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

The last moments of the ill-fated Pompeiians, frozen forever in plaster.

Venice's "Island of the Mad."