A female bodybuilder apples oil to another performer backstage before an amateur competition in the Israeli city of Dimona, in this April 3, 2014 file photo. (Photo by Finbarr O'Reilly/Reuters)

Female bodybuilders prepare to compete in the “Miss Bikini” category of the NABA/WFF Asia-Seoul Open Championship in Seoul on April 17, 2016. (Photo by Ed Jones/AFP Photo)

A Saudi soldier fires a mortar towards Houthi movement position, at the Saudi border with Yemen April 21, 2015. (Photo by Reuters/Stringer)

Soldiers take part in a drill during a heavy snow in Heihe, Heilongjiang province, February 26, 2014. (Photo by Reuters/China Daily)

A line of soldiers firing handguns during a training session, circa 1920. (Photo by Keystone). P.S. All pictures are presented in high resolution.

Three Chinese soldiers at the time of a civil war in China. (Photo by General Photographic Agency/Getty Images). 1922

A French soldier stands near a military combat command vehicle on display at The Defence and Security Exhibition on September 13, 2011 in London, England. ExCeL London is hosting the exhibition with hundreds of manufacturers from all over the world displaying their hardware. (Photo by Peter Macdiarmid/Getty Images)

The annual Victory Day military parade takes place at Red Square on May 09, 2008 in Moscow, Russia. Russia's most important national holiday honours over 26 million Soviet soldiers killed during World War II. Around 8,000 soldiers in newly designed uniforms paraded in the largest Victory Day display of heavy weaponry since the collapse of the Soviet Union. (Photo by Dima Korotayev/Epsilon/Getty Images)