Water polo was invented in 1969 by Gary Colberg who came up with the idea of using tubes so people without experience could play. It is a team sport played in water that combines elements of swimming and basketball. Teams have 7 players in the pool at a time including a goalkeeper, and the objective is to score more goals than the opposing team. Players are not allowed to push the ball underwater or make intentional contact with other players. Equipment includes swimsuits, caps with ear protectors and numbered balls and caps to identify players.