The NFL was formed in 1920 as the American Professional Football Association (APFA) before renaming itself the National Football League for the 1922 season. The NFL agreed to merge with the American Football League (AFL) in 1966, and the first Super Bowl was held at the end of that season; the merger was completed in 1970. Today, the NFL has the highest average attendance (67,591) of any professional sports league in the world and is the most popular sports league in the United States. The Super Bowl is among the biggest club sporting events in the world. The individual Super Bowl games account for many of the most watched television programs in American history, all occupying the Nielsen's Top 5 tally of the all-time most watched U.S. television broadcasts by 2015. The NFL's executive officer is the commissioner, who has broad authority in governing the league. The players in the league belong to the National Football League Players Association.
The Heidi Game or Heidi Bowl was an American football game played on November 17, 1968. The home team, the Oakland Raiders, defeated the New York Jets, 43–32. The game is remembered for its exciting finish, as Oakland scored two touchdowns in the final minute to overcome a 32–29 New York lead. The Heidi Game obtained its name because the National Broadcasting Company (NBC) controversially broke away from the game with the Jets still winning to air the television filmHeidi at 7 p.m. in the Eastern Time Zone. In the late 1960s, few professional football games took longer than two and a half hours to play, and the Jets–Raiders three-hour time slot was thought to be adequate. A high-scoring contest, together with a number of injuries and penalties for the two bitter American Football League rivals, caused the game to run long. NBC executives had ordered that Heidi must begin on time, but given the exciting game, they decided to postpone the start of the film and continue football coverage. As 7 p.m. approached, many members of the public called NBC to inquire about the schedule, to complain or opine, jamming NBC's switchboards, and the change could not be communicated. Heidi began as scheduled, preempting the final moments of the game and the two Oakland touchdowns in the eastern half of the country, to the outrage of viewers. The Heidi Game led to a change in the way professional football is shown on network television; games are shown to their conclusion before evening programming begins. To ensure that network personnel could communicate under similar circumstances, special telephones (dubbed "Heidi phones") were installed, with a connection to a different telephone exchange from other network phones. In 1997, the Heidi Game was voted the most memorable regular season game in pro football history.