The recovered bones of martyrs slaughtered during The Terror are on display in this church crypt.

Jesus' footprints and the first catacombs in the world.

At the crypt of St. Mary of Eulogies and the Dead you are left alone to ponder mortality among piles of skulls.

This Italian pyramid is said to hold the mingled remains of the dead from both sides of the Battle of Novara.

This modern French ossuary contains the jumbled bones of 130,000 WWI soldiers.

This small chapel is built of human bones and decorated with a golden skeleton.

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

An ancient ossuary in Rouen.

Charnel house at the foot of Mount Sinai.

5,000 skulls in memorial to those killed by the Khmer Rouge.

The personal charnel house of Anton Bruckner.

Thousands of well-dressed mummies below a monastery.

Mysterious painted skulls in Moravia.

The mortal remains of an estimated 70,000 people lie in the basement of a monastery in Lima, Peru.

The remains of 40,000 humans, meticulously stacked in a tiny churchyard shed.

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

This Peruvian bone silo lined with hanging human skeletons and hundreds of skulls is topped with a remarkable Michelangelo replica.

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.

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

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

A 1,000-year-old church holds the bones of the Christian martyrs who died hiding inside it.