Buddha shrines hide within dark tunnels at this unique forest temple.

Bangkok's men with dangerous jobs come here in search of protective talismans.

This abandoned prison was so notorious that its name has become a metaphor throughout Albania.

Once the fallout shelter of a dictator, this sprawling bunker is now a combined history museum and contemporary art gallery.

An Albanian monument to the Communism that nearly crushed the country is now a crumbling wreck.

A museum dedicated to secret surveillance.

A non-profit that uses the impressive smelling abilities of African Pouched Rats to find and clear unexploded land mines.

A Bulgarian monument to Russia's role in World War II is constantly being painted in pop culture protest.

Underneath this Byzantinian church lies a necropolis filled with ancient tombs and the ruins of previous churches.

Eastern Bloc nostalgia, anybody?

Ruins of a late 1950s Polish ski jump ramp in the middle of the city.

Imperial palace of Emperor Galerius, the Emperor behind the worst Christian persecutions during the Roman Empire.

Ruins of an old water tower that look like a horror-film castle.

A misnamed well, with a deep dark past.

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

The remains of the left arm of the levitating philosopher-saint are kept in a 13th-century Neapolitan basilica.

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

Dug as a secret royal escape route, the tunnel became a wartime bomb shelter and dumping ground for vintage cars.

An underground paleo-Christian burial site composed of the remains of several cemeteries and Basilicas.

A labyrinth of ancient tunnels hidden below the city holds the ruins of 2,500 years of history.

The townhouse where the "Blood Countess" Elizabeth Báthory started her murderous career.

Vienna's underworld of tunnels and subterranean rivers made an iconic appearance in a 1949 Orson Welles film.

The topiary maze at the Habsburg hunting lodge.

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