Members of La Legion, an elite unit of the Spanish Army, including a goat they use as a pet wait for the start of a military parade as they celebrate a holiday known as “Dia de la Hispanidad” or Hispanic Day in Madrid, Wednesday, October 12, 2016. (Photo by Daniel Ochoa de Olza/AP Photo)

An Army Sikorsky R-5 helicopter, undergoing record trials, demonstrates its lifting power by carrying 17 persons and pilot aloft as female onlookers wave in Bridgeport, Conn., January 10, 1946. During the tests records were claimed for altitude speed and both altitude and speed with payload. (Photo by Anthony Camerano/AP Photo)

An army tank fires during a firefight against militants linked to al Qaeda near the southern Yemeni city of Zinjibar May 30, 2012. (Photo by Reuters/Yemen's Defence Ministry)

An Afghan National Army (ANA) helicopter flies over a soldier during a training exercise at the Kabul Military Training Centre in Afghanistan October 7, 2015. (Photo by Ahmad Masood/Reuters)

Army soldiers prepare a military elephant for the parade during a rehearsal for Sri Lanka's 68th Independence day celebrations in Colombo, February 2, 2016. (Photo by Dinuka Liyanawatte/Reuters)

Army paratroopers carry the casket of Private Howard at the Wellington Cathedral on December 21, 2010 in Wellington, New Zealand. Private Howard was serving with the British army when was killed by friendly fire from a US Air Force plane in Helmand Province, Afghanistan earlier this month. Private Howard is the fifth NZ-born soldier to be killed in action in Afghanistan. (Photo by Marty Melville/Getty Images)

U.S. Army Sgt. Patricia Foust receives a free Christmas tree on December 7, 2011 at Fort Carson in Colorado Springs, Colorado. More than 600 soldiers and military families at the base chose trees as part of the annual Trees for Troops program. (Photo by John Moore/Getty Images)

Free Syrian Army fighters stand near an ambulance on the eastern edge of the northern Syrian town of al-Bab, Syria, February 27, 2017. (Photo by Khalil Ashawi/Reuters)