This ancient Roman prison is decorated with an upside-down cross not as blasphemy but as saintly tribute.

This real life asylum of horrors is now an abandoned ruin that hides the unbreakable code to one patient's insanity.

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

A complex, nine-layer maze on the grounds of a Venetian doge's playground.

The martyr's wax-enhanced skeletal remains lie preserved in a glass case in the Santa Maria della Vittoria in Rome.

The location of the last witch trials of Italy, known as "The Salem of Europe."

This former Roman Catholic Church still contains the embalmed hearts and organs of 22 popes.

Crushed coral and crystals give the sand its signature coloration.

Filled with goldfish swimming in a shallow pool of sea water, this ancient crypt is more wishing well than burial site.

Pilgrimage site for star-crossed lovers.

Natural cathedral designed by Italian artist Giuliano Mauri.

David Sedaris called it "The greatest shop in the world."

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

This beautiful park on the outskirts of Rome protects the ruins of two colossal ancient aqueducts.

Abandoned medieval hill town.

Ruins of a 10th century church tucked away deep in a botanical garden.

This domed temple was built in a hidden cave mouth as a refuge for sinners seeking absolution.

This enchanting 600-year-old tree is so magical it inspired the beloved tale of Pinocchio.

An Italian hillside ghost town.

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

A large grotto built in the 16th century amidst Florence's famous Boboli gardens.

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

Stalactites and stalagmites in a beautifully lit cave.

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