Children attend a swim training session at Hangzhou Chen Jinglun Sport school Natatorium, where Chinese Olympic swimmer Sun Yang and Fu Yuanhui also trained, in Hangzhou, Zhejiang province, China, August 10, 2016. (Photo by Aly Song/Reuters)

A girl looks at other children practicing on a boxing ring during an exercise session at a boxing school, in the Mare favela of Rio de Janeiro, Brazil, June 2, 2016. For many young residents the Luta Pela Paz (Fight For Peace) academy offers a glimpse of an alternative: a chance to build discipline and self-esteem through boxing and martial arts. (Photo by Nacho Doce/Reuters)

Women practice swimming with mermaid tails at AquaMermaid swimming school, a mermaid training school in Chicago, United States on March 19, 2017. Participants are fulfilling their lifelong ambitions of becoming mermaids with a new type of fitness mermaid swimming. (Photo by Bilgin S. Amaz/Anadolu Agency/Getty Images)

Paramedics care for a woman who is ill after the Geelong Cup on Geelong Cup day at Geelong Racecourse in Melbourne, Australia, 19 October 2016. The Geelong Racing Club was founded in March 1865 at a public meeting at the British Hotel. The first Geelong Cup was held in 1872 over a distance of two miles. (Photo by Tracey Nearmy/EPA)

Members of the audience sit in the centre of the catwalk as the watch models for the C/MEO Collective walk by at Fashion Week Australia in Sydney on May 17, 2017. (Photo by Jason Reed/Reuters)

Several new species of peacock spider – just a few millimetres long and featuring extraordinary colours – have been discovered in Western Australia and South Australia. Jürgen Otto, a biologist from Sydney, has been researching the arachnids since 2005, and has gained a significant following online with his footage. He believes there are now 48 confirmed species of peacock spider within the Maratus genus, found across Australia but particularly in Western Australia – and many more awaiting confirmation. Here: Maratus Tasmanicus, one of seven new species of peacock spiders studied by the Sydney biologist Jürgen Otto. (Photo by Jürgen Otto)

Students carry a female trainee who has fallen into a stupor during high intensity training at Tianjiao Special Guard/Security Consultant camp on the outskirts of Beijing December 1, 2013. Former Chinese soldier Chen Yongqing has big ambitions for his bodyguard training school Tianjiao, which he says is China's first professional academy to train former soldiers and others as personal security guards. Chen charges 500,000 yuan ($82,400) a year for each protector as China's rich and famous look to bolster their safety and sense of importance. (Photo by Jason Lee/Reuters)