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
Mauritania at the 2000 Summer Olympics Los Angeles Olympics, and have sent a delegation to every Summer Olympic Games since; they have yet to make their first appearance at the Winter Olympic Games. These Sydney Olympics were the nation's fifth appearance at a Summer Olympiad. The 2000 Summer Olympics were held from 15 September to 1 October 2000; a total of 10,651 athletes represented 199 NOCs. The Mauritanian delegation consisted of two track and field athletes, Sidi Mohamed Ould Bidjel and Fatou Dieng. Ould Bidjel was selected as the flag-bearer for the opening ceremony. Fatou Dieng was 16 years old at the time of the Sydney