The vast, legendary catacombs hold secrets much stranger than stacked bones.

Thousands of well-dressed mummies below a monastery.

These 17th-century mummies are no longer naturally preserved, but remain on display today.

Underneath this small church are 15,000 bones, arranged by an obsessive academic.

A burial vault located under Tiber Island in the middle of the Italian capital.

Ancient catacombs form the foundation for this Rococo orgy of a church.

These lesser-known Maltese catacombs date back over 1,700 years.

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

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

Overshadowed by other, more famous Maltese catacombs, this ancient burial chamber has one of the best examples of a ritual agape table.

The burial place of an obscure North African saint was turned into a macabre body preservation factory for the 17th-century Neapolitan elite.

A maze of underground tunnels beneath one of the most beautiful forts in Serbia.

This German bone house contains the remains of some 20,000 souls.

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

This natural "sea of stones" was once used by the Romans as a quarry.

The name doubles as an appropriate adjective for this small ossuary.

One of the best collections of wax anatomical models in the world.

A glimpse into the festive and private lives of medieval Europe.

The resting place for anonymous victims of the Danube's dark waters.

This cubist Vienna church building looks like some sort of alien stonehenge.

Op-art architecture designed for happiness.

Macabre museum devoted to historical Viennese murders.

Built to give thanks for the passing of a plague epidemic, this cathedral is a one-of-a-kind architectural hybrid.

The final resting place for the remains of 143 Habsburg royalty.