A porter stands at the bottom of the Illimani mountain, on the outskirts of La Paz, Bolivia, April 16, 2016. For years, Lydia Huayllas, 48, has worked as a cook at base camps and mountain-climbing refuges on the steep, glacial slopes of Huayna Potosi, a 19,974-foot (6,088-meter) Andean peak outside of La Paz, Bolivia. But two years ago, she and 10 other Aymara indigenous women, ages 42 to 50, who also worked as porters and cooks for mountaineers, put on crampons – spikes fixed to a boot for climbing – under their wide traditional skirts and started to do their own climbing. (Photo by David Mercado/Reuters)

Auxiliary Territorial Service (ATS) plotters at work at Coastal Artillery Headquarters in Dover, December 1942. The Auxiliary Territorial Service was the women's branch of the British Army during the Second World War. It was formed on 9 September 1938, initially as a women's voluntary service, and existed until 1 February 1949, when it was merged into the Women's Royal Army Corps. The ATS had its roots in the Women's Auxiliary Army Corps (WAAC), which was formed in 1917 as a voluntary service. During the First World War its members served in a number of jobs including clerks, cooks, telephonists and waitresses. The WAAC was disbanded after four years in 1921. (Photo by Ted Dearberg/IWM/PA Wire)

Nopparat (R), a 24-year-old transgender, and a Buddhist monk (L) wait to speak to officers during an army draft held at a school in Bang Na in Bangkok April 3, 2015. Thai men over 21 must serve in the army. Those who volunteer serve six months, but others choose the annual lottery, which goes on for 10 days in recruitment centres around Thailand. Only those not considered physically capable of service, the mentally ill and those who have significantly altered their physical appearance, such as transgenders, are exempt. Picture taken April 3, 2015. (Photo by Athit Perawongmetha/Reuters)

Ethnic Wa performer dressed as United Wa State Army (UWSA) soldiers perform a traditional dance in Mongmao, Wa territory in northeast Myanmar October 1, 2016. Wa State is an unrecognised state in Myanmar (Burma) and is currently subsumed under the official Wa Special Region 2 of northern Shan State. The Wa were once known as the “Wild Wa” by the British due to their practice of headhunting. (Photo by Soe Zeya Tun/Reuters)

Students hold their weapons before the swearing in ceremony for the military students, in Bucharest, Romania, Wednesday, October 25, 2017. The Romanian Army is proudly celebrating their Army Day and marking 100-years since the landmark battle of Marasesti, a key World War I battle in 1917 when Romanian and Russian soldiers defeated German troops, halting a German offensive. (Photo by Vadim Ghirda/AP Photo)

A rider on horseback competes in the Margalla Festival Tent Pegging Championship in Islamabad, Pakistan, June 5, 2016. Tent pegging is an equestrian sport popular in India and Pakistan, with a history going back to the cavalries of ancient armies. (Photo by Caren Firouz/Reuters)

Female members of the Chinese People's Liberation Army (PLA) honour guard stand behind a string to ensure that they are in a straight line before a welcoming ceremony for Russian President Vladimir Putin outside the Great Hall of the People in Beijing, China, June 25, 2016. (Photo by Kim Kyung-Hoon/Reuters)

A US Army M1A2 SEP tank participates in the Strong Europe Tank Challenge 2017 at the military training area in Grafenwoehr, Germany, 12 May 2017. Six North Atlantic Treaty Organization (NATO) nations and partner nations, Austria, France, Germany, Poland, Ukraine and the USA are taking part in this competing exercise. (Photo by Christian Bruna/EPA)