World Solar Challenge is happening this week in Australia — this is the international race on solar cars, which are the cars with the electric engine that use solar energy. This year 43 teams from 25 countries participate in the race. The participants need to race through Australia, from North to the South, from Darwin to Adelaide, which is slightly over 3,000 kilometers. The first person to cross the continent on the solar car was adventurer Hans Tholstrup (it took him 20 days to travel 4,000 kilometers from the West to the East), and starting from 1987 these races are held regularly, and are now held biennially. There is no race track, the racers use regular roads. The average speed of solar cars is the same as for regular cars, and their maximum speed can reach over 100 km/h. However, the speed limit in Australia is 110 km/h anyway. The photo shows Tokai Challenger of Tokai University Japan on day four of the race.