Crumbling ruins of the thermal baths that once attracted royals and aristocrats from throughout Europe.

The abandoned ruins of a failed resort hide on this verdant, picture-perfect island.

Nestled in the hills of Tuscany are gorgeous, multicolored hot springs.

An open-air museum in a mountain valley features works designed to blend in with—and disintegrate back into—their natural surroundings.

These gutted monastery ruins still stand proudly in the middle of the Italian countryside.

A once-luxurious, now abandoned hotel in the Italian Alps.

Italian cave with exceptional acoustics and an unsavory history.

An ancient artistic garden parlor full of hidden water wonders.

Virgil's many-mouthed gateway to the underworld.

Water and windows define this defensive Italian well.

Crossing this suspension bridge feels like walking through the sky, a fitting tribute to the head of the Apollo program.

This lovely little bridge hidden in a Switzerland gorge is essentially a fairytale.

This Italian foot path winds through the mountains via 52 individual tunnels.

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

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

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

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.

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

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

Thousands of well-dressed mummies below a monastery.

Geothermal waterfalls in Tuscany.

A 16th-century horror show built in a lovely Italian garden.