In this October 14, 2013 photo, ecology professor Ricardo Freitas catches a broad-snouted caiman to examine, then release back into the water channel in the affluent Recreio dos Bandeirantes suburb of Rio de Janeiro, Brazil. Caimans are like tanks, a very old species with a remarkable capacity for renovation that allows them to survive under extreme conditions where others couldn't, said Freitas, who runs the Instituto Jacare, or the Caiman Institute, which aims to protect the reptiles. (Photo by Felipe Dana/AP Photo)

Girls practice sit-ups during gymnastics lessons at the Shanghai Yangpu Youth Amateur Athletic School in Shanghai, China, on May 4, 2016. China's sports system has been enormously successful since the country returned to the Olympic fold in 1980, culminating with the host nation topping the medals' table at the 2008 Beijing Olympics. And yet, with the Rio de Janeiro Games less than three months away, the system is beginning to break down due to the shifting demographics of a more prosperous nation. (Photo by Aly Song/Reuters)

Downhill bikers Kemal Mulic (R-L), Tarik Hadzic and Kamer Kolar train on the disused bobsled track from the 1984 Sarajevo Winter Olympics on Trebevic mountain near Sarajevo, Bosnia and Herzegovina, August 8, 2015. Abandoned and left to crumble into oblivion, most of the 1984 Winter Olympic venues in Bosnia's capital Sarajevo have been reduced to rubble by neglect as much as the 1990s conflict that tore apart the former Yugoslavia. (Photo by Dado Ruvic/Reuters)

Gold Medalist Kristof Milak of Hungary during the medals ceremony of the 200m Butterfly final on day five of the swimming competition of the Tokyo 2020 Olympic Games at Tokyo Aquatics Centre on July 28, 2021 in Tokyo, Japan. (Photo by Aleksandra Szmigiel/Reuters)

Poland's Piotr Lisek reacts after competing in the men's pole vault qualification during the Tokyo 2020 Olympic Games at the Olympic Stadium in Tokyo on July 31, 2021. (Photo by Aleksandra Szmigiel/Reuters)

Switzerland's Belinda Bencic celebrates after defeating Czech Republic's Marketa Vondrousova during their Tokyo 2020 Olympic Games women's singles tennis final match at the Ariake Tennis Park in Tokyo on July 31, 2021. (Photo by Yara Nardi/Reuters)

Henna Katarina Johansson (R) of Sweden competes with Marwa Amri of Turkey during the Wrestling Women's Freestyle 62kg 1/8 final at the Tokyo 2020 Olympic Games in Chiba, Japan, Aug. 3, 2021. (Photo by Xinhua News Agency/Rex Features/Shutterstock)