Eco-village hidden in the foothills of the Alps that created a massive system of psychedelic underground temples.

This medieval Italian town is a sheer (and beautiful) cliffside defense.

Medieval town turned hippie commune, once home to the secret foreskin of Jesus Christ.

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

Skulls from the plague of 1656 and World War II bombings are united by a cult dedicated to caring for the ancient dead.

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

Five candy-colored villages on the Italian Riviera.

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

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 skull of the patron saint of lovers lies in the Basilica di Santa Maria in Cosmedin—maybe.

Sitting on an Italian hilltop is this surreal fortress built by the mad inventor of electrohomeopathy.

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

Geothermal waterfalls in Tuscany.

According to the local folklore, the myriad colors of this lake are the result of a lovelorn wizard's blunder.

Thousands of well-dressed mummies below a monastery.

Stalactites and stalagmites in a beautifully lit cave.

The underground sanctuary of a mysterious ancient cult.

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

The middle finger of modernity.

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

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

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

An expansive complex of subterranean tunnels is all that remains of one of Europe's most formidable medieval fortresses.