Summer Olympic Games Australia (1956, 2000) and Brazil (2016). Africa has yet to host a Summer Olympics. Stockholm, Sweden, has hosted events at two Summer Olympic Games, having been sole host of the 1912 Games, and hosting the equestrian events at the 1956 Summer Olympics (which they are credited as jointly hosting with Melbourne, Australia). Amsterdam, Netherlands, has also hosted events at two Summer Olympic Games, having been sole host of the 1928 Games and previously hosting two of the sailing races at the 1920 Summer Olympics. At the 2008 Summer Olympics, Hong Kong provided the venues for the equestrian events, which took
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