If you were making the joke I think you were , then I ' m sorry it flew over everyone ' s heads . <| sep |> This may not be a full answer , but in places like Arlington National cemetery , they don ' t remove graves if they can avoid it . Instead they now severely restrict who can be buried there . Even then , the majority must be cremated and are then placed in a mausoleum . Then there ' s places like many very old cemeteries in Eastern Europe where people were just buried on top of people over and over as many as they could fit on top of others . Mass graves are also another answer . During the repeated outbreaks of plague in Europe , there often wasn ' t enough space for the dead . They were then buried in mass graves . And of course , someone else mentioned the catacombs under paris . This was a direct answer to the city ' s graveyards being overwhelmed .