List of World Series champions
The World Series is the annual championship series of Major League Baseball (MLB) and concludes the MLB postseason. First played in 1903, the World Series championship is determined through a best-of-seven playoff and is a contest between the champions of baseball's National League (NL) and American League (AL). Often referred to as the "Fall Classic", the modern World Series has been played every year since 1903 with two exceptions: in 1904, when the NL champion New York Giants declined to play the AL champion Boston Americans; and in 1994, when the series was canceled due to the players' strike.
Professional sports
In 1871 the first professional baseball league was created. By the beginning of the 20th century, most large cities in the eastern United States had a professional baseball team. After several leagues came and went in the 19th century, the National League (founded in 1876) and American League (recognized as a major league in 1903) were established as the dominant leagues by the early 20th century. The most victorious team in each league was said to have won the "pennant;" the two pennant winners met after the end of the regular season in the World Series. The winner of at least four games (out of a possible seven) was the champion for that year. This arrangement still holds today, although the leagues are now subdivided and pennants are decided in post-season playoff series between the winners of each division.