The only remaining collection of flayed figures made by French "madman" Honoré Fragonard.

Artfully arranged bones of 5,800 Austrians.

Ancient Greek oracle of the dead.

An underground city of salt.

A cave network located at the southernmost tip of mainland Greece was once believed to be an entrance to Hades.

Temple complex that once housed the famous statue of Nike.

An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

The crypt of the imposing Stephensdom holds royal intestines and thousands of skeletons.

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

Thousands of well-dressed mummies below a monastery.

These tombs were built into the side of a mountain so that ancient angels could reach the dead.

A Turkish ghost town abandoned in a population exchange with Greece.