Hidden in a high mountain cave, this hermitage dates back to the ninth century.

An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

This breathtaking monastery was established by Saint Benedict himself 1,500 years ago.

The hermit's humble home is hidden near the forested peak of Monte Marrone.

A 2,000-year-old engineering wonder hides beneath an Italian town.

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

South of Bologna, a limestone grotto with a protruding waterfall and a floor full of cave pearls.

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

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

Visit a secretive crypt before it crumbles to dust.

Stumbling upon this whimsical wooded garden is like stepping into an enchanted forest full of philosophical musings.

Also known as the Temple of Poseidon, this is one of the best-preserved Greek temples in the world.

Ride a boat through this magnificent underground world, which now doubles as a theater.

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

A dreamlike medieval church dug into the tuff rock, with unusual carvings and possible traces of the Templar knights.

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

This ancient altar emerges from the thick forests to reveal the mysteries of Etruscan sacrificial rituals.

The remains of a town so thoroughly destroyed by French forces that the citizens simply left.

This immaculate and historic water garden culminates in a massive stone dining table with an inset fountain for chilling the wine of the Cardinal's guests.

A theme park that suffered massive flooding during Katrina was abandoned, and now proves irresistible to trespassing explorers.

Come for the boats, stay to explore the intriguing assortment of art.

Since it formed millions of years ago, this cave system has been a sacred burial ground, a Prohibition-era speakeasy, and the center of an amusement park.

148 feet long and in the middle of a verdant forest.

Famous for its bio-luminescent inhabitants, known as "dismalites."