Prior to 1970, before the NFL incorporated the then-competing American Football League in the NFL-AFL merger, the Super Bowl was played between the champions of the two separate football leagues. The NFL was widely viewed as superior to the AFL, and the Packers, an NFL team, had handily won the first two Super Bowls. Everything changed with Super Bowl III, when the AFL-champ Jets pulled off the biggest upset in Super Bowl history. The Jets, led by "Broadway" Joe Namath, who guaranteed victory prior to the game, handily beat a Baltimore Colts team that was considered one of the greatest ever at the time.

Nothing about the Giants suggested greatness going into the playoffs. They made the playoffs as a wild card team after limping down the stretch, losing two of their last three games. Giants quarterback Eli Manning had never won a playoff game. They were the underdogs in every playoff game they played. Yet, the Giants knocked off three straight division winners on the road before taking on the then-undefeated Patriots in the Super Bowl. Then the unthinkable happened - the Giants took down the Patriots juggernaut in a thrilling game, and likely the biggest Super Bowl upset in post-merger NFL history.

Going into this game, most football fans expected to see a dynasty established, as the "Greatest Show on Turf" St. Louis Rams were heavily favored to win their second championship in three seasons. But a funny thing happened - the Patriots, led by rookie quarterback Tom Brady - became the dynasty instead, going on to win two of the next three Super Bowls. These Patriots came out of nowhere, starting the season 0-2 after going 5-11 the previous year, and narrowly escaped a first round defeat in the infamous "Tuck Rule" game.

When you look at the numbers, it's hard to understand how this team made the Super Bowl. They finished 9-7 - still tied for the worst record for a Super Bowl team - and lost their starting quarterback during the season. His replacement, Vince Ferragamo, threw twice as many interceptions as touchdowns. Yet, they turned it on when it mattered, beating Dallas and Tampa Bay (by a 9-0 score) to advance to the Super Bowl, where they lost in the final championship for the Pittsburgh Steelers dynasty.

Like the 1979-80 Rams, this team finished with a 9-7 record. It had a miserable playoff history, with only one playoff win since moving to Arizona in 1988. Yet the Cardinals, led by quarterback Kurt Warner and wide receiver Larry Fitzgerald, got hot at the right time and ran through the NFC playoffs. Like those Rams, this team ultimately succumbed to the Steelers in the Super Bowl, but not before giving them everything they could handle in a thrilling game.

Like the 2002 Patriots, this team was quite a surprise, as the 49ers had finished their prior two seasons with a combined 8-24 record. But led by third-year quarterback Joe Montana, these 49ers matured, going 13-3 despite a very young defensive secondary featuring rookie Ronnie Lott. That nucleus of players became a dynasty, as they went on to win three more Super Bowls over the next eight seasons.

The biggest surprise about this Rams team was how dominant they were despite losing their starting quarterback, Trent Green, to a season-ending knee injury in the preseason. Kurt Warner, an undrafted quarterback with more experience as a grocery bagger and Arena League player than as an NFL player, stepped in to lead the team to one of the greatest offensive seasons in league history. By the time the playoffs began, the Rams were the top seed in the NFC and rolled through the playoffs, edging the Tennessee Titans in one of the most thrilling Super Bowls in recent memory.

Even though the 1968-69 Jets had shocked the world the year before, becoming the first AFL team to win the Super Bowl, the AFL-champion Chiefs still were heavy underdogs to the Minnesota Vikings and their legendary "Purple People-Eater" defense. After starting quarterback Len Dawson went down to injury, little was expected from the Chiefs, but their stout defense carried them through a narrow win over the Raiders in the AFL championship game and brought the team their only Super Bowl win.

The Steelers, led by second-year quarterback Ben Roethlisberger, started the season 7-5 and were the sixth seed in the AFC entering the playoffs. But the Steelers were not ready to go home and became the first team ever to beat all three of the top-seeded teams in the conference on the road to reach the Super Bowl, where they won the franchise's fifth championship by outlasting the NFC champion Seattle Seahawks.

The Bills had lost the prior two Super Bowls, and going into the season it may not have been a bold choice to pick them to make the big game for the third straight year. But it certainly would have been early in the third quarter in the wild card round, when they trailed the Houston Oilers 35-3. The Bills then scored five straight touchdowns - without their starting quarterback, no less - and won the game in overtime, in a game so great that it is simply known as "The Comeback." The Bills ultimately were crushed by the Cowboys in this and the next Super Bowl, and have not returned since.

Led by young quarterback John Elway, the Broncos were a team on the rise entering the 1986-87 season. They finished with an 11-5 record and won their division. This run became surprising, however, when the team narrowly escaped the opening round and then found themselves down seven points with 5:32 to play in the AFC championship game in Cleveland. Elway led his team 98 yards down the field, in what is now known simply as "The Drive," and tied the game. The Broncos won in overtime, ripping out the hearts of Browns fans. Alas, the Broncos were then crushed by the New York Giants in the Super Bowl in what would become the first of three embarassing Super Bowl losses for Denver over the next four years.

These Bengals were a mirror image of the 49ers team that defeated them in the Super Bowl, except that they didn't blossom into a dynasty. Prior to the 1981-82 season, the Bengals had never won a playoff game and were coming off a 6-10 record. That all changed as they finished with a 12-4 record and then knocked off the Bills and Chargers - in a game known as the Freezer Bowl because of the nearly negative-40 degree wind chill in Cincinnati that day - before succumbing in the Super Bowl.

What made this team surprising was not so much that they won, but rather how they won. Journeyman quarterback Trent Dilfer was easily one of the worst quarterbacks ever to make - much less win - a Super Bowl, and the offense routinely had difficulty moving the ball. However, Baltimore's dominating defense - likely the best in league history - allowed a total of 16 points in three playoff wins as the wild card Ravens advanced to the Super Bowl. They then annihilated the Giants 34-7 in a boring game, though it did feature back-to-back kickoff returns for touchdowns, the only time that has ever happened in the Super Bowl.