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)

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)

The second of six C-17 Globemaster III airlifters for the United Arab Emirates Air Force and Air Defence is being assembled at the Boeing assembly facility on May 10, 2011 in Long Beach, California. The UAE will take delivery of three more C-17s this year and two in 2012 as it modernizes its airlift capabilities. (Photo by Kevork Djansezian/Getty Images)

Women walk next to soldiers in Surcubamba, Peru, Thursday, May 21, 2015. The Joint Command of the Peruvian Armed Forces organized a humanitarian mission to Surcubamba, where health care was provided to families from nearby villages in this region called VRAEM, the acronym for Valley of the Apurimac, Ene and Mantaro rivers, where sixty percent of Peru's cocaine originates. (Photo by Rodrigo Abd/AP Photo)

Iraqi security forces take part in training, as they prepare to fight against militants of the Islamic State, at a training camp on the outskirts of Mosul January 10, 2015. (Photo by Azad Lashkari/Reuters)

In this Saturday, March 21, 2015 photo, a porter rests carrying supplies for the upcoming climbing season, near the Everest Base camp, Nepal. Nepal has cleared more than 300 mountaineers to climb Mount Everest after they had to abandon last year's efforts when an ice avalanche killed 16 guides in the mountain's deadliest disaster, an official said on March 20. The three-month climbing season for Everest, the world's tallest mountain, begins in March. (Photo by Tashi Sherpa/AP Photo)