This Italian church is as beautiful as it is common, except for the real skulls decorating the many mannequins inside.

A complex, nine-layer maze on the grounds of a Venetian doge's playground.

The plague quarantine island home to the alleged "Vampire of Venice."

A small island less than half a mile from Venice is a forbidden island with a dark and twisted past.

Venice's "Island of the Mad."

A museum of magic with a Sadist past.

The largest and most famous wax anatomical collection anywhere in the world.

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

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

The underground sanctuary of a mysterious ancient cult.

St. Francesca Romana, patron saint of drivers, resides in the church she founded.

A Nesting Doll of Churches.

Charles Dickens was not a fan of the ghastly wall dressings in this 6th century church.

An alchemist's "magic door" stands in the middle of a Roman park.

A curious collection dedicated to human and animal anatomy and pathology.

Ancient man-made caves underneath small town Belgium.

Legendary site where an evil bishop was devoured by rodents.

Terrifying derelict military hospital once housed a recuperating Hitler.

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

The resting place of 18th century German mummies.

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

The walls and ceiling of this Polish church are decorated with thousands of skulls, with another 21,000 skeletons just below.

Silent memorial, using bone conduction to take people back to the Dresden Bombing of 1945.

A museum of alchemy and a basement laboratory all housed in an ancient building in a Gothic tower.