One of the largest ossuaries in Spain is packed from floor to ceiling with bones.

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

A house of bones — but nobody is quite sure to whom they belong.

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

In 1830, cemetery workers in Cham unearthed a chamber housing thousands of skeletal remains from the 13th century, which can still be viewed today.

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

A church filled with the bones of hundreds of virgins martyrs—or so they say.

This landmark church concealed a crypt packed with bones that was discovered thanks to the London Blitz.

In a small churchyard in Dingolfing, Germany the quaint Schusterkapelle is there to remind you of your imminent mortality.

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

Structure built from the skulls of vanquished foes.

The mystery of the Putim Ossuary involves a tricorn hat.

A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

An ancient rogue artist community hidden next to one of the world's most glitzy and glamorous cities.

The location of the last witch trials of Italy, known as "The Salem of Europe."

This magnificent museum claims to house the cranium of a disciple and the skull of a pope.

One man's personal kunstkammer, museum and shop.

King Ludwig I's collection of beautiful women.

This curious sculpture represents the perseverance needed to take to the skies.

Visitors can explore the role of mysticism throughout the ages inside this interactive museum of magic.

Beneath the impressive baroque cathedral that rises from the center of Berlin lies the largest collection of Prussian royals in the world.

Home to 10,000 medical specimens including the remains of Rudolf Virchow's extensive collection of pathological specimens.

An eerie, derelict amusement park in Berlin.

One of ancient Etruria's most spectacular archaeological sites with impressive necropolises and rugged landscape.