Cuban soldiers receive combat training at the Cadets School “Antonio Maceo” November 28, 2001, 30 kilometers East of Havana. (Photo by Jorge Rey/Getty Images)

Travellers stop to take a second glance at a model of a giant lady with her head stuck in a photo booth being exhibited in Victoria train station on September 21, 2007 in London, England. (Photo by Cate Gillon/Getty Images)

An instructor from the Tianjiao Special Guard/Security Consultant Ltd. Co, smashes a bottle over a female recruit's head during a training session for China's first female bodyguards in Beijing January 13, 2012. (Photo by David Gray/Reuters)

Peruvian surfer Domingo Pianezzi rides a wave with his alpaca Pisco at San Bartolo beach in Lima March 16, 2010. Pianezzi has spent a decade training dogs to ride the nose of his board when he catches waves, and now he is the first to do so with an alpaca. (Photo by Pilar Olivares/Reuters)

People cool off in a fountain outside the Southbank Centre on June 30, 2015 in London, England. The UK is currently experiencing a heatwave, with temperatures of 35 degree celsius forecast tomorrow in some parts of the country. The extreme heat has already seen train cancellations and a health warning has been issued. (Photo by Rob Stothard/Getty Images)

Soldiers of People's Liberation Army (PLA) Lanzhou Military Region jump through a burning obstacle during a training session at a military base in Tianshui, Gansu province, China, January 6, 2016. (Photo by Reuters/Stringer)

An Israeli teenager crawls through mud as he participates in an annual combat fitness training competition, as part of his preparations ahead of his compulsory army service, near Kibbutz Yakum, central Israel February 19, 2016. (Photo by Baz Ratner/Reuters)

Soldiers of China's People's Liberation Army (PLA) jump as part of their winter training in temperature of negative 26 degrees Celsius at China's border with Russia in Heihe, Heilongjiang province, December 14, 2015. (Photo by Reuters/Stringer)