After a team scores a touchdown, it is able to add one more point by kicking the football through the uprights of the goalpost. They snap the ball on the three-yard line, which makes this attempt 20 yards for the kickers.
One of the most famous extra points ever missed was after a play called the "River City Relay". The Saints were fighting for a playoff spot at the time, and they found themselves down 20-13 on their own 25 with just seven seconds left. After completing a short pass to one of the Saints, they lateralled the ball to one player, then another, until the play finally transcended into a touchdown. John Carney came on the field to kick an extra point which would have taken the game to overtime. Instead, Carney missed the kick and the Jaguars won 20-19.