The NCAA Men's Division I Basketball Championship is a single elimination tournament held each spring in the United States, featuring 72 college basketball teams, both conference champions and at-large selections. The tournament, organized by the National Collegiate Athletic Association (NCAA), was created in 1939 by the National Association of Basketball Coaches and was the brainchild of Kansas coach Phog Allen Held mostly in March, it is informally known as March Madness or the Big Dance; the tournament, and especially the national semi-finals and final (the Final Four), has become one of the nation's most prominent sporting events.