The first week starts with eight teams competing in the First Four, with the four winners joining 60 teams to compete in the first and second rounds. The tournament consists of seven rounds and is conducted over three successive weeks. Teams are placed in four regions and given a seed between 1 and 16 within the region. These 'at-large' teams are chosen by an NCAA selection committee, then announced in a nationally televised event dubbed Selection Sunday. The tournament teams include champions from 32 Division I conferences and 36 teams which are awarded at-large berths. Known for its upsets of favored teams, it has become one of the biggest annual sporting events in the US. Played mostly during March, the tournament consists of 68 teams and was first conducted in 1939.
The NCAA Division I men's basketball tournament, branded as NCAA March Madness and commonly called March Madness, is a single-elimination tournament played in the United States to determine the men's college basketball national champion of the Division I level in the National Collegiate Athletic Association.
