Bowling for Columbine is a controversial documentary film written, directed, produced by, and starring Michael Moore. The film opened on October 11, 2002 and brought Moore international attention. The film explores what Moore suggests are the causes for the Columbine High School massacre and other acts of violence with guns. Moore focuses on the background and environment in which the massacre took place, and some common public opinions and assumptions about related issues. The film looks into the nature of violence in the United States, focusing on guns as a symbol of both American freedom and its self-destruction. In Moore's discussions with various people, including South Park co-creator Matt Stone, the National Rifle Association's then-president Charlton Heston, and musician Marilyn Manson, he seeks to explain why the Columbine massacre occurred and why the United States has a higher number of violent crimes, especially crimes involving guns and charges that the occurrence of violent crimes in the U.S. is relatively higher than other developed nations.