Students of the General Yermolov Cadet School wait to board an airplane for a parachute jump at an airdrome in the village of Novomaryevskaya outside the southern city of Stavropol, Russia, May 13, 2016. (Photo by Eduard Korniyenko/Reuters)

A Saudi soldier fires a mortar towards Houthi movement position, at the Saudi border with Yemen April 21, 2015. (Photo by Reuters/Stringer)

A man falls from an ox cart as he competes during an ox cart competition near U Bein bridge, in Mandalay March 22, 2015. (Photo by Soe Zeya Tun/Reuters)

Francisco Javier Moreno (L), 35, and his wife Maria Auxiliadora Canca, 34, dressed as bandits pose for a photo with their horse as they participate in the third edition of “Ronda Romantica” (Romantic Ronda) in Ronda, southern Spain, May 16, 2015. Ronda Romantica is a cultural, historical and tourist event during the three days where thousands of people of Ronda and about fifty towns around of “Serrania de Ronda” (Ronda Mountain Ranges), dressed in traditional costumes, recreate the era of the bandits, drovers and romantic travelers in the nineteenth century. (Photo by Jon Nazca/Reuters)

Jimmy Bryan of Phoenix, Ariz., gets the checkered victory flag at the Indiana State Fairgrounds September 17, 1955 as he wins the “Hoosier Hundred” for the second consecutive year. Bryan averaged 83.98 miles an hour for the 100-lap, 100-mile AAA big car race. (Photo by AP Photo)

A participant in the Borodino Battle re-enactment before the show at the Borodino Field in the Moscow Region on September 4, 2016. The Battle of Borodino, fought on September 7, 1812, was a battle fought in the Napoleonic Wars during the French invasion of Russia. The fighting involved around 250,000 troops and left at least 70,000 casualties, making Borodino the deadliest day of the Napoleonic Wars. (Photo by Kirill Kallinikov/Sputnik)

An ethnic Armenian fighter carries Kalashnikov machine guns to his comrade-in-arms at Martakert province in the separatist region of Nagorno-Karabakh, Azerbaijan, Monday, April 4, 2016. (Photo by Vahan Stepanyan/PAN Photo via AP Photo)

A picture released by the North Korean Central News Agency (KCNA) shows Kim Jong-un convening an urgent operation meeting at 0:30 am on March 29, 2013 at an undisclosed location, in which he ordered strategic rocket forces to be on standby to strike US and South Korean targets at any time. (Photo by KCNA via EPA)