The creation of basketball was created by Canadian physical education instructor James Naismith. Naismith was a 31-year old graduate student when he created the indoor sport to keep athletes indoors during the winters. The game grew and became popular very quick as the 20th century progressed. It first got popular in America then in other parts of the world. After basketball became established in American colleges, the professional game followed. The American National Basketball Association (NBA), established in 1946, grew to a multibillion-dollar enterprise by the end of the century, and basketball became a big part of American culture.