The 1975 Pittsburgh Steelers

The 1975 Pittsburgh Steelers quickly discovered that one of the most difficult feats in all of sports is defending a world title. At the beginning of the season, coach Chuck Noll's team didn't even look like they had the stuff to reach the playoffs, let alone win back-to-back championships. Fresh off an upset in Super Bowl IX, the Steelers were not a dynasty just yet, not even with nine future Hall of Fame players. In Week 2, the team lost at home to O.J. Simpson's Buffalo Bills for a 1-1 start. But thanks to their defense, which featured a front four called the "Steel Curtain," the club pounded out 11 straight wins, much to the delight of their blue-collar fans. Still, Pittsburgh's season may be best remembered for the ballet-like moves of wideout Lynn Swann. In Super Bowl X, Swann set a record with 161 receiving yards on four catches, including a game-sealing, 64-yard touchdown grab to beat the Dallas Cowboys and clinch their second-straight Super Bowl title.