An Iraqi Army member launches a rocket during the operation to retake Mosul from Daesh terrorists in Jadid neighborhood as the clashes between Iraqi Army and Daesh terrorists continue in Mosul, Iraq on April 2, 2017. (Photo by Hemn Baban/Anadolu Agency/Getty Images)

A member of the Air Force's Wings of Blue Parachute Demonstration Team salutes as he jumps out of an aircraft, during the opening ceremony of Aviation Nation 2017 Nellis Air and Space Expo at Nellis Air Force Base, Nev., November 10, 2017. (Photo by Senior Airman Kevin Tanenbaum/Reuters/U.S. Air Force)

Medieval jousters Luke Binks (L) and Andrew McKinnon pose for a photograph in Sydney, Australia, August 16, 2017 during a photo call for the World Jousting Championships to take place in Sydney on September 23 and 24. (Photo by Dan Himbrechts/Reuters/AAP)

Chinese Kazakh eagle hunters sit on horseback as they travel to a local competition on January 29, 2015 in the mountains of Qinghe County, Xinjiang, northwestern China. The festival, organised by the local hunting community, is part of an effort to promote and grow traditional hunting practices for new generations in the mountainous region of western China that borders Kazakhstan, Russia and Mongolia. The training and handling of the large birds of prey follows a strict set of ancient rules that Kazakh eagle hunters are preserving for future generations. (Photo by Kevin Frayer/Getty Images)

In this photo taken on Sunday, February 15, 2015 a girl runs away from a “Mamuxarro” during the carnival, in the small town of Unanu, northern Spain. In the northern Spanish ancient village of Unamu, people dress up as “Mamuxarro”, folkloric figures in white with a red sash and a metal mask to cover their faces as they pursue townsfolk with sticks. According to custom, their “victims” (usually young women) must kneel and kiss the mamuxarro’s knee after he makes the sign of the cross on their forehead. (Photo by Alvaro Barrientos/AP Photo)

In this photo released by Xhinhua News Agency, a rescuer evacuates residents near the site of a chemical plant blast in Zhangzhou, southeast China's Fujian Province Tuesday, April 7, 2015. Six people have been hospitalized and hundreds of firefighters deployed to battle a blaze sparked by an explosion at Goure PX Plant that produces the toxic chemical paraxylene, officials said Tuesday. (Photo by Wei Peiquan/AP Photo/Xinhua)

In this photo taken Tuesday, April 14, 2015, immigrant men armed with machetes make their way onto a Durban, South Africa, street during clashes with police and in search of locals that attacked foreign shop owners in the city center. (Photo by Tebogo Letsie/AP Photo)

Entomologist Anna Platoni wears a hat made of tropical flowers made by florist Emma Reynolds with a Blue Morpho butterfly on her cheek to mark the opening of Butterflies in the Glasshouse at RHS Garden Wisley, south of London, on Janurary 15, 2016. (Photo by Luke MacGregor/PA Wire/RHS)