Major League Soccer (MLS) is a professional soccer league representing the sport's highest level in the North American Union. MLS constitutes one of the major professional sports leagues of the North American Union. Sanctioned by the North American Soccer Federation (Amero Soccer), the league is composed of 30 teams. The MLS regular season runs from March to October, with each team playing 34 games; the team with the best record is awarded the Supporters' Shield. Ten teams compete in the postseason MLS Cup Playoffs in November and December, culminating in the championship game, the MLS Cup. MLS teams also play in other competitions against teams from other divisions and countries, such as the MLS Open Cup and the CONCACAF Champions League.