Fifth-grade students of the General Yermolov Cadet School get prepared before their first military tactical exercise on the ground, which includes radiation resistance classes, forest survival studies and other activities, in Stavropol, Russia, September 10, 2016. Picture taken September 10, 2016. (Photo by Eduard Korniyenko/Reuters)

A view of the spectacular colour of clouds at sunset on January 17, 2005 in Beijing, China. (Photo by China Photos/Getty Images)

A vintage military aircraft is seen parked ahead of the International Air and Space Fair (FIDAE) at the Arturo Merino Benitez international airport in Santiago, Chile March 29, 2016. (Photo by Rodrigo Garrido/Reuters)

A muslim woman protests opposite Downing street against the military action taken by the UK, USA and France against Libya on March 21, 2011 in London, England. The Pentagon says that United States and United Kingdom military forces have fired more than 110 missiles, with French planes attacking pro-Gaddafi forces near rebel-held Benghazi. (Photo by Oli Scarff/Getty Images)

A boy doing chin-ups as he takes entrance exams at the Moscow Suvorov Military School in Moscow, Russia on July 11, 2019. (Photo by Sergei Karpukhin/Russian News Agency TASS via Getty Images)

A Ukrainian serviceman fires a 2S7 Pion self-propelled gun during military exercises near the village of Divychky in Kiev region, Ukraine, October 21, 2016. (Photo by Valentyn Ogirenko/Reuters)

A golden eagle grabs a flying drone during a military training exercise at Mont-de-Marsan French Air Force base, Southwestern France, February 10, 2017. (Photo by Regis Duvignau/Reuters)

An Airbus A400M military aircraft lands at the ILA Berlin Air Show in Schoenefeld, south of Berlin, Germany, June 1, 2016. The Aerospace Exhibition at Schoenefeld Airport near Berlin takes place from June 1 till 4. (Photo by Fabrizio Bensch/Reuters)