We all face the eventual end of our lives and, for hundreds of years, we   have sought to commemorate and pay tribute to those who have died as a   way to grieve and put perspective on the meaning of life. Since early in   the history of humankind, we have placed markers or gravestones at the   location of burials. The marker recreates a physical presence of the   lost one that allows others a place to come mourn and grieve. Later, the   marker becomes a remembrance and proof that the one who died had, at   one time, actually been alive. The psychology of most people is that a   marker may be one of the last vestiges of immortality that may survive   far into the future. The marker feeds an innate desire to make a   difference and have it, in some ways, be permanent.