Catacombs of Paris

The Catacombs of Paris in the 14th arrondissement are Europe's largest ossuary: the disused Petit-Montrouge limestone quarries hold the bones of about six million Parisians. The transfers began in 1786 because the overcrowded inner-city cemeteries, above all the Cimetiere des Innocents, were poisoning the soil and groundwater. The bones were moved at night by cart and then arranged with macabre artistry, with rows of femurs forming walls and skulls outlining lines and crosses, while Latin maxims remind visitors of mortality. A signed two-kilometre route now leads twenty metres beneath the street, starting at Place Denfert-Rochereau. Passages can be narrow, the temperature stays at 14 degrees year round and two-hour waits in summer are normal.