A reveller of the Salgueiro samba school performs during the second night of Rio's Carnival at the Sambadrome in Rio de Janeiro, Brazil, on February 13, 2018. (Photo by Mauro Pimentel/AFP Photo)

A reveller from Unidos da Tijuca samba school performs during the first night of the Carnival parade at the Sambadrome in Rio de Janeiro, Brazil on March 4, 2019. (Photo by Pilar Olivares/Reuters)

A boy doing chin-ups as he takes entrance exams at the Moscow Suvorov Military School in Moscow, Russia on July 11, 2019. (Photo by Sergei Karpukhin/Russian News Agency TASS via Getty Images)

Students dressed up as Hindu gods Lord Krishna and Lord Shiva participate in a cultural event in their school in Mumbai, India on August 21, 2019. (Photo by Indranil Mukherjee/AFP Photo)

School boys who attend Sri Lankan traditional dance training wait for their graduation ceremony at a Buddhist temple in Colombo, Sri Lanka January 23, 2017. (Photo by Dinuka Liyanawatte/Reuters)

A coach wipes away tears and comforts a girl who was feeling tired during gymnastics lessons at the Shanghai Yangpu Youth Amateur Athletic School in Shanghai, China, May 4, 2016. (Photo by Aly Song/Reuters)

A picture of Moon Ji-sung, a high school student who died in the Sewol ferry disaster, hangs in her room in Ansan April 7, 2015. Her dream was to be a flight attendant. Nearly a year after the Sewol ferry sank on April 16, 2014, with the death of 250 students, some families keep their children’s bedrooms intact to remember and honour their loved ones. More than 300 people, most of them students and teachers from Danwon High School, are dead, or missing and presumed dead, after the Sewol ferry sank on a routine trip from the port of Incheon, near Seoul, to the holiday island of Jeju. (Photo by Kim Hong-Ji/Reuters)

Young Chinese football players help an injured player off the field during training at the Evergrande International Football School on June 12, 2014 near Qingyuan in Guangdong Province, China. The sprawling 167-acre campus is the brainchild of property tycoon Xu Jiayin, whose ambition is to train a generation of young athletes to establish China as a football powerhouse. The school is considered the largest football academy in the world with 2400 students, more than 50 pitches and a squad of Spanish coaches through a partnership with Real Madrid. (Photo by Kevin Frayer/Getty Images)