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)

A giant new exhibition space created by famed graffiti artist Banksy opens to the public on May 3, 2008 in London, England. The disused tunnel beneath Waterloo station has been transformed by 30 artists from around the world. The three day event, tagged as the “Cans festival”, also invites the public to add their own stencil art. (Photo by Jim Dyson/Getty Images)

An employee of the National Park Service takes a selfie with President Barack Obama, left, in the background meeting with the crowd after a tour of Everglades National Park on Earth Day, Wednesday, April 22, 2015, in Florida. Obama used the visit to warn of the damage that climate change is already inflicting on the nation's environmental treasures. (Photo by Lynne Sladky/AP Photo)

Youths kick a gay rights activist during a protest against a proposed new law termed by the State Duma, the lower house of Parliament, as “against advocating the rejection of traditional family values” in central Moscow June 11, 2013. (Photo by Maxim Shemetov/Reuters)

A driver on the Horseshoe Pass in North Wales wiping the snow from the windscreen of his car during a heavy snow storm, 18th January 1937. (Photo by Norman Smith)

Japanese chorus girls appear to be drilling in military tactics atop their theater building as they perform salutes, June 30, 1937. The officer is from the Japanese regular army and says the girls display more rhythm in their drills than do the regular troops. (Photo by AP Photo)

Jackie Barajas of Chula Vista dressed as Loki at Comic-Con in San Diego, USA on July 22, 2017. (Photo by K.C. Alfred/San Diego Union-Tribune via ZUMA Press/Rex Features/Shutterstock)

Convicted murderer Hector Alvarado Mazariegos, right, drops to the ground as he is hit by bullets of a Guatemala firing squad in the public cemetery at Mazatenango, June 28, 1975. His companion, Rocael Ortiz, met the same fate a few seconds later. Both were convicted of murder. (Photo by AP Photo/Anzueto)