Officers react at their graduation ceremony during Iraqi Army Day anniversary celebration in Baghdad January 6, 2015. Iraqi Defence Minister Khaled al-Obeidi said on Tuesday that the Iraqi military has started rebuilding after its near total collapse last summer but that the effort is still in its initial phase. (Photo by Ahmad Mousa/Reuters)

Members of the Legio X Fretensis (Malta) re-enactment group take part in a display of ancient Roman army life at Fort Rinella in Kalkara, outside Valletta, March 22, 2015. The event “Romanus”, organised by the Malta Heritage Trust, consisted of talks, hands-on displays, static exhibitions of weapons and equipment, food and wine tasting and large-scale re-enactments depicting different forms of Roman warfare in the field. (Photo by Darrin Zammit Lupi/Reuters)

Israeli soldiers of the Search and Rescue brigade take part in a training session in Ben Shemen forest, near the city of Modi'in May 23, 2016. (Photo by Amir Cohen/Reuters)

Soldiers march during a military parade commemorating the 37th anniversary of the founding of the Nicaragua's army, in Managua, Nicaragua September 3, 2016. (Photo by Oswaldo Rivas/Reuters)

North Koreans who signed up to join the army train in the midst of political tension with South Korea, in this undated photo released by North Korea's Korean Central News Agency (KCNA) in Pyongyang August 23, 2015. Top aides to the leaders of North and South Korea resumed talks on Sunday after negotiating through the night in a bid to ease tensions involving an exchange of artillery fire that brought the peninsula to the brink of armed conflict. (Photo by Reuters/KCNA)

An attendee takes a selfie at KCON USA, billed as the world's largest Korean culture convention and music festival, in Los Angeles, California on August 11, 2018. K-pop acts sing or rap in Korean, often with snippets of English. On the Web, where K-pop fandom thrives, many music videos include subtitles. (Photo by Mike Blake/Reuters)

Battle-weary American troops withdraw from Yong San in Korea. (Photo by Keystone/Getty Images). 1950