The 32 teams are organized into eight geographic divisions of four teams each. These divisions are further organized into two conferences, the National Football Conference and the American Football Conference. The two-conference structure has its origins in a time when major American professional football was organized into two independent leagues, the National Football League and its younger rival, the American Football League. The leagues merged in the late 1960s, adopting the older league's name and reorganizing slightly to ensure the same number of teams in both conferences.