A series of caves, tunnels, and wells filled with fascinating figures and symbols.

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

The bizarre visions of H.R. Giger, tucked away in a Swiss medieval city.

This sword isn't waiting for a king to pull it out. It was placed there by a saint.

700 iron sculptures crammed into a Mediterranean park.

The Neapolitan Cult of the Dead still cares for the skulls at this mini-Fontanelle.

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

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

Inside this museum, Christians were imprisoned when the Romans controlled Gaul.

An architect transformed this abandoned cement factory into his castle-like workshop.

A self-built mosaic house and sculpture park.

Figures of unknown origin carved into the surfaces of underground caves.

Ivy-covered Medieval tunnels cut through this charming town in France's Loire Valley.

A well-preserved medieval village nested on a rocky outcrop and surrounded by a network of cliffs, natural bridges and canyons.

Village situated on a narrow volcanic escarpment.

The studio of Catalonia's most famous theatrical designer remains exactly as he left it.

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

A spiritual sanctuary in a natural cave.

One of the great treasures of Neolithic art lies within this carefully constructed pile of rocks.

One of the greatest maze designer’s greatest mazes.

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

The leathery remains of a woman who died in the 13th century now lie in a church named for her.

One of ancient Etruria's most spectacular archaeological sites with impressive necropolises and rugged landscape.

The verdant mossy ruins of a Franciscan monastery lie in the remote Sintra hills awaiting exploration.