The catacombs of Paris are named after those in Rome and similarly serve as an underground cemetery. Like the catacombs in Rome they are located in former stone quarries, occupying a very small perentage of the so-called GRS (Grand Réseau Sud). Unlike Rome, however, they owe their existence to concerns about sanitation rather than religious freedom.
The first internments were made in 1786 from overcrowded surface cemetries that were polluting water sources. A total of perhaps six million bodies now lie underground. It’s difficult to make an accurate assessment since many of the bones are reburied in massed areas of the same bone type, rather than as intact bodies. A few victims of the riots of the French Revolution are believed to have been buried in the catacombs.
Although a tourist site for many years, the current museum opened in 1983 and the visit includes around a kilometre of the underground passages.