Discus throw is an athletics (track and field) event in which a discus-shaped object is thrown for distance. The discus must be thrown from a circle 2.5 metres (8.2 feet) in diameter and land inside a 40 degree sector designated on the ground from the center of the circle in contemporary competition. The maximum possible score on the modern discus is 150 points. The first recorded women's discus championship was held at the 1968 Mexico City Olympics. American Joan Barnes threw 102.4 meters (335.4 feet), one of her best throws, to win the gold medal. She had already won the silver medal at the 1964 Tokyo Olympics and the 1967 World Championships without reaching 100 meters. Canadian Nancy Ennis took home the bronze medal with a throw of 96.0 meters (316.4 feet). This remains the only time that Americans have swept the podium spots on the discus platform. Barnes' performance broke a long-standing Olympic record by over 10 feet and has never been surpassed. She went on to become the first woman to be named USA Track and Field's Athlete of the Year. In total, Americans have won nine of the twenty-one discus medals awarded at the Olympics. The next highest number of winners is Germany with three medals. All but one of these medals have gone to women. At the international level, the event is used to determine qualification for the Olympics and world championships.