This 16th-century monastery has been turned into a surrealist architecture compound.

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

This ancient Roman prison is decorated with an upside-down cross not as blasphemy but as saintly tribute.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

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

A sulfuric hellscape in southern Italy.

The once forbidden "secret cabinet" of erotic art from excavations of Pompeii and Herculaneum.

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

An Italian ghost town that fought obscurity, until a mysterious illness brought it to its knees.

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

Virgil's many-mouthed gateway to the underworld.

Ruins of a German Castle on top of a towering stone pillar.

A church of bones, decorated with 40,000 human skeletons.

Two monstrous faces loom over a village in Czechia.

A collection of anatomical samples from one of the first anthropologists to suggest that humans reached North America by crossing the Bering Strait.

Erotic art covers the walls of the largest ancient pleasure palace.

A submerged archeological park still holds the wonders of a Roman Sodom.

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

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

Ruins of a 10th century church tucked away deep in a botanical garden.

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

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

Largest necropolis in the Mediterranean.

Jesus' footprints and the first catacombs in the world.