During the 20th century, football was the most popular sport in the United States. It made its Olympic debut at the London Games in 1908. It also appeared in each Summer Games since 1908. Football is the second-most popular sport worldwide. It is played in more than 200 countries and has a huge fan base.
The goal of football is to score more goals than the opposition in 90 minutes of playing time. The game is played between two teams that are generally paired. Each team aims to score points by running with the ball, passing the ball, or taking shots at the goal. Each team has its own playbook, ranging from dozens to hundreds of plays.
The rules of the game were set out by the Football Association in 1863. They established the foundations of modern football.
In modern football, each play is called a down. Each team is required to get at least ten yards from its starting point. If a team fails to get ten yards, the ball is forfeited to the other team.
A goal kick occurs when the ball crosses the goal line. A touchdown is worth six points to the team scoring the goal.
An incomplete pass is a forward pass that touches the ground before being caught. A safety is scored when the offensive player is tackled in the end zone.
A fumble is a lost ball. If the team recovers the ball, the player runs with it until he or she is tackled.