Catacombs of Paris

The Catacombs of Paris or Catacombes de Paris are underground ossuaries in Paris, France. Located south of the former city gate (the "Barrière d’Enfer" at today's Place Denfert-Rochereau), the ossuaries hold the remains of about six million people and fill a renovated section of caverns and tunnels that are the remains of historical stone mines, giving it its reputation as "The World's Largest Grave". 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, it was closed to the public in September 2009 and reopened on 19 December of the same year.^[2]

• http://en.wikipedia.org/wiki/Catacombs of Paris