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

A contestant for Miss Tiffany's Universe Thailand 2018 gets ready backstage during the annual transgender beauty contest “Miss Tiffany's Universe Thailand 2018” at the Tiffany's Show Theatre in Pattaya city, Chonburi province, Thailand, 31 August 2018. Thirty Thai transgender contestants took part in the final stage of the annual beauty contest which is aimed to promote the tourism industry in the resort city of Pattaya city. (Photo by Narong Sangnak/EPA/EFE)

Contestants compete in the swimsuit segment of the Miss Venezuela 2012 pageant in Caracas August 30, 2012. The winner of the competition will participate in the 2013 Miss Universe pageant. (Photo by Carlos Garcia Rawlins/Reuters)

A humanoid dental patient robot, named Hanako Showa, about to be used during a demonstration of dental treatment at Showa University on March 25, 2010 in Tokyo, Japan. The robot was co-developed by the university and tmsuk co. Ltd, and simulates real human patients. The robot has been used for training of procedures in which the dental treatment requires a high level of precision. (Photo by Koichi Kamoshida/Getty Images)

A participant of the “Mrs Universe 2015” contest from Caribbean Coast, Mayra Joli poses for a photo with a woman during their visit in central botanical garden in Minsk, Belarus, August 25, 2015. (Photo by Vasily Fedosenko/Reuters)