Basketball is a uniquely American sport. It originated in 1891 when James Naismith, a young physical education teacher in Springfield, Massachusetts, was instructed by his boss to invent a new game that could be played indoors during the cold winter months to keep the students occupied and out of trouble. Naismith thought back to his boyhood in Canada, where he and his friends had played "duck on a rock," which involved trying to knock a large rock off a boulder by throwing smaller rocks at it. He also recalled watching rugby players toss a ball into a box in a gymnasium. He had the idea of nailing up raised boxes into which players would attempt to throw a ball. Naismith had two bushel baskets, used for carrying peaches, nailed to the balcony at opposite ends of the school’s gymnasium. He set up two nine-man teams, gave them a soccer ball, and told them the object was to toss it into the basket being defended by the opposing team. Most of the rules Naismith drew up still apply in some form today. He called the game Basket Ball, the modern version of which is played by over 250 million people worldwide in an organized fashion, as well as by countless others in "pick-up" games.