The Fontaine des Innocents is located at the formed major graveyard of Paris: Cimetière des Innocents.
Used from the 12th to 18th centuries, the graveyard became overcrowded. Corpses even fell through the ground into cellars of surrounding buildings. It was a serious source of diseases. Paris got struck twice with cholera epedemics. A solution was urgently needed.
In the mean time, a lot of buildings in Paris were submerging due to the collapsing of old underground corridors and quarries of limestone. They came to the conclusion that piling up the bones in the corridors would support the corridros and prevent collapsing. All of the bodies of Cimetière des Innocents were exhumed.
They transported millions of skeletons to the subterranean quarries near Montparnasse that are best known as the Catacombs.
Fontaine des Innocents