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

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

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

Ancient snack bar of the Roman Empire re-opened.

Italian cave with exceptional acoustics and an unsavory history.

These medieval skyscrapers dominate the skyline of this small Tuscan town.

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

Museum dedicated to literary greats of the Romantic Period is also the home in which Keats met his untimely end.

The astonishing collection of an infamous criminologist.

Venice's island of the dead.

A hospital where antique dolls are given new life.

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

Pilgrimage site for star-crossed lovers.

The final resting place of the poets Shelley and Keats.

An ossuary built in 1210 to collect bones from the Ospedale Maggiore of Milan.

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

The glowing blue Nymphaeum of Emperor Tiberius.

Venice's "Island of the Mad."

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

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

Geothermal waterfalls in Tuscany.

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

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

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