The history of American football can be traced to early versions of rugby football. Among the major changes instituted by Walter Camp, considered the "Father of American Football", in the 19th century were the introduction of the line of scrimmage and of down-and-distance rules. In the late 19th and early 20th centuries, gameplay developments helped take advantage of the newly introduced forward pass. The popularity of collegiate football grew as it became the dominant version of the sport for the first half of the twentieth century. Bowl games, a college football tradition, attracted a national audience for collegiate teams. Bolstered by fierce rivalries, college football still holds widespread appeal in the US. Meanwhile, the origin of professional football can be traced back to 1892. In 1920, the National Football League (NFL) was formed, and eventually became the major league of American football. Football's increasing popularity is usually traced to the 1958 NFL Championship Game, a contest that has been dubbed the "Greatest Game Ever Played". A rival league to the NFL, the American Football League, began play in 1960; the pressure it put on the senior league led to a merger between the two leagues and the creation of the Super Bowl, which has become the most watched television event in the United States on an annual basis. (more...)