Sixty feet beneath the surface of the 14th Arrondissement in southern Paris are a complex of tunnels called the catacombs. This is where building stone (limey yellowish sandstone, the color of Paris) was quarried until the late 18th Century. Once these artificial caves grew too large, they began collapsing, jeopardizing surface buildings. The subterranean hollows were then reinforced and repurposed to house human bones from the terribly overcrowded surface cemeteries, some of which were so choked with bones that they stood eight feet higher than the surrounding terrain. Seven million people are buried here. The official policy forbids photography in the catacombs, but the underpaid guards do not enforce this rule.

Another history of the catacombs

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