From Reuters:March 13, 1996 - BRITAIN - Gunman Thomas Hamilton burst into a primary school in the Scottish town of Dunblane and shot dead 16 children and their teacher before killing himself. April 28, 1996 - AUSTRALIA - Martin Bryant unleashed modern Australia's worst mass murder when he shot dead 35 people at the Port Arthur tourist site in the southern state of Tasmania. April 1999 - UNITED STATES - Two heavily-armed teenagers went on a rampage at Columbine High School in Littleton, Denver, shooting 13 students and staff before taking their own lives. July 1999 - UNITED STATES -...