Ice racing is a form of racing that uses cars, motorcycles, snowmobiles, all-terrain vehicles, or other motorized vehicles. Ice racing takes place on frozen lakes or rivers, or on groomed frozen lots. As cold weather is a requirement for natural ice, it is usually found at higher latitudes in Canada, the northern United States, and in northern Europe, although limited indoor events are held in warmer climates, typically on ice hockey rinks (motorcycles and ATVs only). Tracks in North America vary from 1/4 mile to several mile-long (~400 m to several kilometer-long) circuits.