The NCAA Division I men's basketball tournament, branded as March Madness, or The Big Dance, 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 (NCAA). Played mostly during March, the tournament was first conducted in 1939 and currently consists of 68 teams. Known for its upsets of favored teams with its single game single-elimination format, it has become one of the greatest annual sporting events in the US.