Members of the local Cossack community undergo military training at a boot camp set up by the Russkiye Vityazi (Russian Knights) military patriotic club in the village of Sengileyevskoye, south of Stavropol, March 22, 2015. A group of cossacks from the village of Kazanskaya, who are planning a professional career at the military intelligence service, has arrived at a camp for training under the leadership of professional instructors. (Photo by Eduard Korniyenko/Reuters)

Yang Shiguang, 77, performs stunts at a park in Xi'an, Shaanxi province, September 3, 2013. Yang has been a member of a stunt performance club since 2007, after retiring from a research institution. (Photo by Reuters/China Daily)

A spiritual leader (R) of the Huni Kui Indian tribe blows an herbal powder into the nose of a tribal member during a ceremony outside the village of Novo Segredo along the Envira river of Brazil's northwestern Acre state, March 9, 2014. Many indigenous groups, including the Huni Kui, Ashaninka, and Madija, live in villages in the Brazilian rainforest near the border with Peru. (Photo by Lunae Parracho/Reuters)

Former NBA player Yao Ming (R), a member of the 12th Chinese People's Political Consultative Conference (CPPCC) National Committee, is seen during an interview in Beijing, China, in this picture taken March 9, 2016. (Photo by Reuters/China Daily)

A Russian Soyuz MS space capsule stands on the ground shortly after its landing with International Space Station (ISS) crew members Kate Rubins of the U.S., Anatoly Ivanishin of Russia and Takuya Onishi of Japan, as a rescue helicopter lands nearby, outside the town of Dzhezkazgan (Zhezkazgan), Kazakhstan, October 30, 2016. (Photo by Dmitri Lovetsky/Reuters)

An officer reviews members of the honor guard as they line up before a welcoming ceremony for visiting Mozambique's President Filipe Jacinto Nyusi at the Great Hall of the People in Beijing, Wednesday, May 18, 2016. (Photo by Mark Schiefelbein/AP Photo)

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)

Members of the Wasteland Warriors from the movie “MadMax” pose during the Wacken Open Air festival on August 4, 2016 in Wacken, Germany. Wacken is a village in northern Germany with a population of 1,800 that has hosted the annual festival, which attracts heavy metal fans from around the world, since 1990. (Photo by Alexander Koerner/Getty Images)