Jackie Robinson Day (United States)

Jackie Robinson Day is a traditional event which occurs annually on April 15 in Major League Baseball (MLB), commemorating and honoring the day Jackie Robinson made his major league debut. Celebrated at MLB ballparks, on that one day, all players, coaches, and managers on both teams, and the umpires, wear Robinson's uniform number, 42. April 15 was Opening Day in 1947, Robinson's first season in the major leagues.