This futuristic German spa allows visitors to float in a pool of salt water while zoning out to underwater techno.

The iconic boulevard is the perfect place to catch sight of a bicycling skeleton, a levitating Satan, or a chef with his head stuck in a pizza.

An unusual stroll through gentlemen's erotica demonstrates that pornography is timeless.

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

The burial place of an obscure North African saint was turned into a macabre body preservation factory for the 17th-century Neapolitan elite.

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

A popular legend claims that the famous pizza was invented at a restaurant in this alley.

The glowing blue Nymphaeum of Emperor Tiberius.

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

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

Ancient snack bar of the Roman Empire re-opened.

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

Before it was buried by volcanic ash, this fast-food restaurant fed the hungry hordes of ancient Rome.

The walls and streets of the ancient city are peppered with penises.

A unique seaside cave where Aleister Crowley faked his own death.

A New York–based physician returned home to Spain to build his own elaborate monument to Christopher Columbus.

Touching this little fossil embedded in the wall of a grand mosque-cathedral may make your wishes come true.

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

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

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

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

Caves that can't seem to quit producing the remains of prehistoric humans.

Local lore says a serpent-like beast lurks in the deep basin below the falls.

These otherworldly caverns form Earth's oldest known cave system.