Who are the most popular sports?

Baseball has a huge following and is referred to as the "national pastime"; Major League Baseball teams play almost every day from April to October. Professional baseball began in the United States around 1865, and the National League was founded in 1876 as the first true major league. The World Series is the championship series of Major League Baseball, the culmination of the sport's postseason each October. It is played between the pennant winner of the American League and the pennant winner of the National League. The Series winner is determined through a best-of-seven playoff. Notable baseball players include Babe Ruth, Sandy Koufax, and Nolan Ryan. Baseball and its cousin, softball, are also popular participatory sports in the U.S.