American soldiers leaping from an armoured personnel carrier during exercises in Korea, 17th March 1954. (Photo by Three Lions)

A soldier walks on the bank of the river in central Pyongyang, North Korea on April 16, 2017. (Photo by Damir Sagolj/Reuters)

A National Army of Colombia soldier, who was wounded by a mine, swims at a pool in Bello, municipality of Antioquia, March 25, 2015. (Photo by Fredy Builes/Reuters)

An American soldier walks ahead of an MKIV (Mark IV) British-made tank, circa 1918. (Photo by Hulton Archive/Getty Images)

James Castrission, “Cas” and Justin Jones “Jonesy” ski across an ice staking rink with two “You Can” patients on August 2, 2011 in Sydney, Australia. In 75 days, the Aussie adventure pair will attempt to cross 2,200 kilometres of Antarctic ice to the South Pole and back on foot to raise money for youth with cancer. The journey will require the two to trek with all the supplies for approximately three months of walking. Cas and Jonesy became the first to kayak unassisted over 3,300 kilometres from New Zealand to Australia in 2008. (Photo by Ryan Pierse/Getty Images)

Giant panda Jia Jia enjoys her birthday cake made with ice and vegetables at Ocean Park in Hong Kong, Tuesday, July 28, 2015 as she celebrates her 37-year-old birthday. Jia Jia broke the Guinness World Records title for “Oldest Panda Living in Captivity” on Tuesday. (Photo by Kin Cheung/AP Photo)

In this Sunday, June 4, 2017 photo, a model walks the runway wearing a design by Agatha Ruiz de la Parada on the final day of Miami Fashion Week at Ice Palace Film Studios in Miami. (Photo by Bryan Cereijo/Miami Herald via AP Photo)

A picture made available on 09 October 2016 shows competitors during a Legion Run event, in Sofiko near the city of Corinth, Greece, 08 October 2016. Legion Run is run covering five kilometres with obstacles of mud, fire, ice and barbed wire, which takes place in different countries around the globe. (Photo by Vassilis Psomas/EPA)