This unique Renaissance castle was turned into a home for Nazi occultism.

Super-heavy Nazi architectural experiment.

Living trees form the structure of an open-air palace.

Terrifying derelict military hospital once housed a recuperating Hitler.

Art and a pun, all in one.

A state-of-the-art medical facility from the Imperial era is now a derelict ruin.

The largest free-standing aquarium in the world resides in a hotel lobby in Berlin.

The birthplace of an eccentric alchemist and possible inspiration for the fictional reanimator of monsters.

Started as a kitchen garden, now the second largest botanical garden in the world.

This jaw-dropping 19th-century bridge uses its reflection to form what appears to be a perfect circle.

An eerie, derelict amusement park in Berlin.

The Bourbon royal family had this unique octagonal hunting "cottage" built on a tiny islet in Lake Fusaro.

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

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

Hidden beneath the famous St. Peter's Basilica is a veritable city of the dead that may hold the remains of St. Peter himself.

Ever hear of the Milazzo Cage?

The oldest volcanology research center in the world.

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

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

Stalactites and stalagmites in a beautifully lit cave.

Contains some of the world's more disturbing wax anatomical models.

The mark of the Devil's horns on a marble column in Milan.

This magical-looking island is notorious for the misfortunes suffered by its owners.

Anatomical cabinet holds unexpected treasures.