After the merger in 1970, the 26 teams in the league were divided into two conferences consisting of three divisions. At that time, four teams from each conference advanced to the playoffs. The team with the best record aside from the three division winners earned a wild card berth. In the first round of the playoffs, the top seed would host the wild card team, unless they were in the same division. When that occurred, the division winner with the worse record would face the top team. The winners from both conferences would meet in the Super Bowl.
The AFC champion Baltimore Colts defeated the NFC champion Dallas Cowboys 16-13 in the first Super Bowl since the merger. The 1972 Miami Dolphins are currently the only team to go undefeated, finishing the year 17-0. Miami won the Super Bowl again the following year. The Pittsburgh Steelers rose to prominence in the mid-seventies, winning four Super Bowls. The NFL added an additional wild card berth in 1978. By 1990, six teams from each conference made the playoffs.
When the expansion Houston Texans entered the NFL in 2002, the playoffs expanded to 12 teams total. The Pittsburgh Steelers and San Francisco 49ers have both won five Super Bowls. The Dallas Cowboys have won four. The NFL’s single elimination playoff system contributes to the league’s soaring popularity among sports fans. The Super Bowl is the only professional championship of the major sports decided on a neutral field. It is the most watched event in the country. Many believe it should be national holiday.