Pere Lachaise is the largest graveyard in Paris and is 43 Hectares. It was first opened in 1804 and has several famous people buried here. The most visited grave is that of Jim Morrison. It was crazy trying to see Jim's grave because there were a lot of people there all crowding the grave and not moving away. We literaly had to push our way in.
The Catacombs were old Roman stone quarries filled in the 18th and 19th centuries with the overflow from the cemeteries. The sides of the under-ground route are constructed from the bones of some 6 million people.