Formula One, also known as Grand Prix racing, is the highest class of auto racing defined by the Fédération Internationale de l'Automobile (FIA), motor sport's world governing body. The "formula" in the name is a set of rules which all participants and cars must meet. The F1 world championship season consists of a series of races, known as Grands Prix, held usually on purpose-built circuits, and in a few cases on closed city streets. The results of each race are combined to determine two annual World Championships, one for drivers and one for constructors.