The known history of the catacomb—meaning an underground cemetery—dates back to first-century Rome, but the most well-known came into being elsewhere in Europe in the 17th century. Overcrowding in Paris’s more traditional burial spaces, as well as sanitation issues, led to a transformation. Miles of tunnels connecting old stone quarries under the city were reused as crypts. It’s believed that more than six million people were laid to rest in the underground labyrinth. In some places, bones and skulls line the walls, sometimes crafted into intricate works of art. Paris might get the headlines (and inspire the occasional maze), but such sprawling crypt networks exist all over the world.
In the city of Leon, Mexico, stands the beautiful Templo Expiatorio, a neo-Gothic church that also provides entry to an underground world below. Formed by a connection of seven different crypts, the catacomb below has cramped, dark corridors that contain the remains of nearly 2,000 people. Elsewhere, the Catacombs of Washington, D.C., were created by Franciscan monks who wanted to make a reflection of the Holy Land for those who couldn’t afford the trip overseas. The crypts underneath the Franciscan Monastery of the Holy Land in America still contain at least one skeleton. From catacombs across Malta to little known collections of bones beneath monasteries, here are some of our favorite chill-inducing labyrinths of the dead.