Afghan National Army (ANA) soldiers sit waiting to return their weapons after a day of traning at the Kabul Military Training Center (KMTC) October 3, 2010 in Kabul, Afghanistan. There are between 5,000 to 7,000 troops on the training facility in eight-week cycles trained by the coalition forces to ultimately take over the role of military operations in the country. (Photo by Paula Bronstein/Getty Images)

Željava Air Base, situated on the border between Croatia and Bosnia and Herzegovina under Plješevica Mountain, near the city of Bihać, Bosnia, was the largest underground airport and military air base in the former Yugoslavia, and one of the largest in Europe. (Photo by Thomas Windisch/Exclusivepix Media)

PALEMBANG, SUMATRA, INDONESIA - NOVEMBER 14: Fitriyani Fitriyani (L) of Indonesia and Janice Ng (R) of Singapore compete in the Sport Climbing Womens Speed Track Finals on day four of the 2011 Southeast Asian Games at Jakabaring Sports Complex on November 14, 2011 in Palembang, Sumatra, Indonesia. (Photo by Matt King/Getty Images)

Canadian soldiers from the Royal 22nd Regiment take up a position during a non-combative extraction operation in a simulated village as part of Rim of the Pacific (RIMPAC) 2016 exercise held at Camp Pendleton, California United States, July 11, 2016. (Photo by Mike Blake/Reuters)

Mask dancers take part in a parade during the the International Festival of Masquerade Games “Surva” in the town of Pernik, some 30 km from Sofia, Bulgaria, 27 January 2019. In ancient times the old Thracians held the Kukeri Ritual Games in honor of god Dionysus – known as a god of wine and ecstasy. Even today these games are also known as the Dionysus' games. Among the Kukeri dancers' are many characters, including Dionysus and his satyrs as well as others from deep history such as the tsar, harachari, plyuvkachi, startzi, and pesyatzi. (Photo by Vassil Donev/EPA/EFE)

A indigenous man from the Tabajara tribe is seen in Tocantins river before the I World Games for Indigenous People in Palmas, Brazil, October 21, 2015. (Photo by Ueslei Marcelino/Reuters)

Brazilian natives of the Pareci tribe play head football with a hand-made ball for a demonstration, during the first day of the International Games of Indigenous Peoples, in Cuiaba, state of Mato Grosso, on November 10, 2013. 1500 natives from 49 Brazilian ethnic groups and from another 17 countries are gathering in Cuiaba until November 16 to compete in some 30 athletic disciplines, many of their own. (Photo by Christophe Simon/AFP Photo)