Tombstones or as they are often called Monuments mark the location of graves and appear to be an almost universally practiced ritual of death.  In ancient times, graves in the Land of Israel were specifically marked, so that persons would know the location of graves and would thereby avoid becoming ritually impure by walking over a grave. Hundreds of thousands of tombstones even survive from the Roman period. Tombstones serve to record the history of mankind on a very personal scale.