In the early Roman Empire, people deemed traitors and criminals were tossed to their deaths from this rock.

A wunderkammer of curious objects and intriguing art nestled within a hub of ancient Roman sites.

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

This statue is the only female representation of Rome's "talking statues."

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

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

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

At the crypt of St. Mary of Eulogies and the Dead you are left alone to ponder mortality among piles of skulls.

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

Virgil's many-mouthed gateway to the underworld.

Italy's "New Mountain" rose from the ground in a volcanic eruption in 1538.

Italy's third-largest Roman arena gives a peek into the underground operations beneath the ancient spectacles.

A sulfuric hellscape in southern Italy.

A rococo room covered entirely in porcelain originally constructed for another royal residence.

An underground paleo-Christian burial site composed of the remains of several cemeteries and Basilicas.

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

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

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

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

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

This industrial area was the dumping ground for massive amounts of trash, some of which washes up as tiny bits of sea glass.

A prehistoric landscape hidden in the cliffs of Maha'ulepu.

Submerged lava formations create incredible waterworks.

A once-glowing grotto at the bottom of Waikapalae Wet Cave.