Summer Olympic Games when Tokyo again becomes host city. Historically, the Summer Olympics has been held predominantly in English-speaking countries and European nations. Tokyo will be the first city outside these regions to have hosted the Summer Olympics twice; it will also be the largest city ever to have hosted the Games, having grown considerably since 1964. The 2016 Games in Rio de Janeiro, Brazil, were the first Summer Olympics to be held in South America and the first that were held during the local winter season. The only two countries in the Southern Hemisphere to have hosted the Summer Olympics have been
Olympic Games detect banned substances. Several athletes were barred from competition by their National Olympic Committees prior to the Games; only three athletes failed drug tests while in competition in Beijing. In London over 6,000 Olympic and Paralympic athletes were tested. Prior to the Games 107 athletes tested positive for banned substances and were not allowed to compete. During and after the Games eight athletes tested positive for a banned substance and were suspended, including shot putter Nadzeya Ostapchuk, who was stripped of her gold medal. Russia was partially banned from the 2016 Summer Olympics and completely banned from the 2018 Winter