Summer Olympic Games demand for tickets to all levels of each event, there was controversy when seats set aside for sponsors and National Delegations went unused in the early days. A system of reallocation was put in place so the empty seats were filled throughout the Games. Rio de Janeiro, Brazil hosted the 2016 Summer Olympics, becoming the third city in the Southern Hemisphere to host the Olympic Games after Melbourne, Australia, in 1956 and Sydney, Australia, in 2000, and the first South American city to host the Olympics. The preparation for these Games was overshadowed by controversies, including the instability of Brazil's
Olympic Games performance-enhancing drugs. There was a sharp increase in positive drug tests at the 2000 Summer Olympics and 2002 Winter Olympics. Several medallists in weightlifting and cross-country skiing were disqualified because of doping offences. During the 2006 Winter Olympics, only one athlete failed a drug test and had a medal revoked. The IOC-established drug testing regimen (now known as the Olympic Standard) has set the worldwide benchmark that other sporting federations attempt to emulate. During the Beijing games, 3,667 athletes were tested by the IOC under the auspices of the World Anti-Doping Agency. Both urine and blood tests were used to