Football originated in the United Kingdom between the 7th and 19th centuries and began as an unorganized game played with animal bladders. In the 19th century, standardized rules were established, and it became an Olympic sport in 1900. A football match involves two rival teams of 11 players each wearing matching uniforms who can hit the ball with any part of their body except hands in an attempt to score more goals than their opponent within a 90-minute game consisting of two 45-minute halves.