What is the only NFL team to go undefeated in a season and then win the Superbowl?

Miami Dolphins

Answer: The 1972 Dolphins are the only National Football League team to complete an entire season undefeated from the opening game through the Super Bowl (or championship game). The undefeated campaign was led by coach Don Shula and notable players Bob Griese, Earl Morrall, and Larry Csonka. The 1972 Dolphins went 14–0 in the regular season and won all three post-season games, including Super Bowl VII against the Washington Redskins, to finish 17–0.