Festival goers attend day one of the Parklife Festival at Heaton Park on June 9, 2018 in Manchester, England. (Photo by Mercury Press)

Donna Vekic of Croatia poses during a portrait session held on February 9, 2012 in London. (Photo by Clive Brunskill/Getty Images)

Freshmen in Zhengzhou Institute of Aeronautical Industry Management head bottles of mineral water for upright stand during military training on September 17, 2015 in Zhengzhou, Henan Province of China. More than 6,800 freshmen in the school are required to take part in the military training. (Photo by ChinaFotoPress/ChinaFotoPress via Getty Images)

These images of young children training were taken at a gymnastics summer camp in Bozhou, Anhui province, China on July 28, 2015. Children with promise are selected to attend, and their families hope training will not only benefit their children physically but also increase ‘willpower’, according to China News Service. (Photo by ChinaFotoPress/ChinaFotoPress via Getty Images)

Soldiers from Japan's Ground Self Defense Force come ashore in amphibious assault vehicle as they train alongside U.S. Marines during the bilateral annual Iron Fist military training exercise in Camp Pendleton, California February 26, 2016. (Photo by Mike Blake/Reuters)

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)

An exhausted and frustated migrant holds his head after he missed to get a place on a train heading to the Serbian border at the train station in Gevgelija, The Former Yugoslav Republic of Macedonia, August 13, 2015. From the beginning of the year to mid-June 2015, nearly 160,000 migrants landed in the southern European countries, mainly Greece and Italy, on their way to wealthier countries in Western and Northern Europe, according to estimates by the International Organization for Migration (IOM). (Photo by Georgi Licovski/EPA)

A child attends a training session in a swimming pool on July 10, 2007 in Wuhan of Hubei Province, China. (Photo by China Photos/Getty Images)