A fascinating assortment of cave dwellings, medieval ruins, and sarcophagi are being devoured by the forest.

Explore the quarry where the marble was sourced for Michaelangelo's David.

Every inch of this chapel is covered in craftsmanship from across the world.

Cave shrine on Monte Pellegrino.

A spiritual sanctuary in a natural cave.

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

Drink wine handed out through a window as part of an age-old tradition.

A slightly creepy gallery of plaster cast models in the same museum as Michelangelo's David.

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

A madman's personal garden filled with 1,000 sculpted heads.

An Italian geologic wonder that served as the inspiration for the landscape of Dante's hell.

The best preserved Paleochristian basilica in Rome hides a number of oddities and secrets.

A massive natural rock arch gives the Tuscan mountain its own window to the sky.

A sulfuric hellscape in southern Italy.

These delicate sand pyramids look like naturally occurring gothic spires.

This mosaic-lined medieval church was built by the world's first admiral and still holds mass in ancient Greek.

A lover's walk between hilltop towns, decorated with graffiti love notes.

The Roman Emperor's lost summer home and grotto full of enormous sculptures sit along the Italian seashore.

Italian cave with exceptional acoustics and an unsavory history.

This shining multicolored metro station deep under Naples is said to be the most beautiful in Europe.

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

The sinister ruins of one of the worst dam failures of the 20th century lie in this astonishing alpine setting.

One of the largest caves in the world open to the public.

This picturesque Umbrian city has a subterranean side that has long remained hidden.