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

Isolated atop this Balinese sea crag is a lovely Hindu temple that is said to be guarded by sea snakes.

Two ancient Buddhist temples crown this dramatic rocky pinnacle.

This isolated structure beckons adventurers with sublime views of the Faroe Islands.

An unfinished tomb carved into a giant boulder in the Arabian Desert.

The "Greatest Sewer" of ancient Rome is one of the oldest sewer systems in the world, and is still in use.

This ancient Roman prison is decorated with an upside-down cross not as blasphemy but as saintly tribute.

St. Francesca Romana, patron saint of drivers, resides in the church she founded.

Jesus' footprints and the first catacombs in the world.

One of seven Jewish catacombs in Rome and one of only two open to the public.

Hidden beneath the famous St. Peter's Basilica is a veritable city of the dead that may hold the remains of St. Peter himself.

The underground sanctuary of a mysterious ancient cult.

Science fiction's grandfather has a fittingly marvelous tomb.

The encased skull that is widely believed to belong to St. John the Baptist.

The mystery of the Putim Ossuary involves a tricorn hat.

Skeletons dressed in extravagant 18th century royal costumes cavort in the aisles of this German basilica.

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

Naturally preserved bodies are eerily staged throughout the crypt in varying poses.

Ruins battered by centuries of war and disaster offer a wondrous glimpse of medieval Ireland.

Seventeen members of the local royal family are interred in this Baroque church in northern Germany.

Built on a medieval synagogue, this church has a burial crypt, tunnel system, and Jewish ritual bath hiding deep underneath.

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

This isolated island is often capped by its own fluffy cloud.

A neo-Gothic church built to thank God for saving the Emperor of Austria from an assassination.