Mines Of Tunnel Network, Catacombes De Paris, Paris, France

The Catacombs of Paris (French: Catacombes de Paris) are underground ossuaries in Paris, France which hold the remains of over six million people in a small part of the ancient Mines of Paris tunnel network. Located south of the former city gate "Barrière d’Enfer" (Gate of Hell) beneath Rue de la Tombe-Issoire, the ossuary was founded when city officials were faced with two simultaneous problems: a series of cave-ins starting in 1774 and overflowing cemeteries, particularly Saint Innocents. Nightly processions of bones from 1786 to 1788 transferred remains from cemeteries to the reinforced tunnels, and more remains were added in later years. The underground cemetery became a tourist attraction on a small scale from the early 19th century, and has been open to the public on a regular basis since 1874 with surface access from a building at Place Denfert-Rochereau.
The Catacombs are among the 14 City of Paris Museums managed by Paris Musées since January 1, 2013. The catacombs are formally known as l'Ossuaire Municipal or Catacombes officiels and have been called "The World's Largest Grave" due the number of individuals buried. Although the ossuary covers only a small section of the underground "les carrières de Paris" ("the quarries of Paris"), Parisians today often refer to the entire tunnel network as "the catacombs".