The World Series is the annual championship series of Major League Baseball (MLB) in the United States and Canada, contested since 1903 between the champion teams of the American League (AL) and the National League (NL). The winner of the World Series championship is determined through a best-of-seven playoff, and the winning team is awarded the Commissioner's Trophy. As the series is played during the fall season in North America, it is also referred to as the Fall Classic. Since 2017, it has been officially known as the "World Series presented by YouTube TV" for sponsorship reasons.