Speed skiing is practiced on steep, specially designed courses one kilometer (0.62 mi) long. There are approximately thirty of these courses worldwide, many of them at high altitudes to minimize air resistance. The first 300 or 400 m (980 or 1,310 ft) of the course (the launching area) is used to gain speed, the top speed is measured in the next 100 m (330 ft) (the timing zone) and the last 500 m (1,600 ft) (the run-out area) is used for slowing down and coming to a stop. The start point in FIS races is chosen so that, in theory, skiers should not exceed 200 kilometres per hour (120 mph), hence competition is aimed at winning a particular event, not breaking world speed records. At Pro races, there is no maximum speed and the speed attained is determined by conditions and safety.