Located south of the former city gate (the "Barrière d'Enfer" at today's Place Denfert-Rochereau), the ossuary holds the remains of about 6 million people and fills a renovated section of caverns and tunnels that are the remains of Paris's stone mines. Opened in the late 18th century, 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 from 1874. Following an incident of vandalism, they were closed to the public in September 2009 and reopened 19 December of the same year. The official name for the catacombs is l'Ossuaire Municipal. Although this cemetery covers only a small section of underground tunnels comprising "les carrières de Paris" ("the quarries of Paris"), Parisians today often refer to the entire tunnel network as "the catacombs".