Burial grounds for more than 1,000 bodies deep under the modern town of Rabat.

The prototype for all Nazi concentration camps.

Museum about life, death, and cannibalism in the Stone Age.

The largest catacomb system in the world.

An artist's mausoleum with a haunting echo.

Of course Salvador Dalí lived in a castle...

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

The final resting place of the poets Shelley and Keats.

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

Natural mummies hidden in the crypt of a medieval French church.

Europe's second largest ossuary wasn't discovered until 2001.

An Irish church where an 800-year-old mummy is reaching out of his coffin as if to shake hands.

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

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

An Austrian house of bones filled with hundreds of intricately painted skulls.

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

The seamy, underground secrets of Portland's criminal past.

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

Mexico's astounding mummy museum with "the world's smallest mummy."

Mummified monks and the accidentally interred, in a 17th-century crypt.

A 16th century chapel decorated with bones, skulls, and entire bodies hanging from the wall.

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

Thousands of well-dressed mummies below a monastery.

Open for a weekend once a year around October it houses a fascinating collection of unique Victorian preserved and stuffed animals.