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

American soldiers leaping from an armoured personnel carrier during exercises in Korea, 17th March 1954. (Photo by Three Lions)

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)

Lance Sergent Martin Mitchell (R) pins medals to Coldstream Guardsman Martin Hughes in the Tailor Shop in Wellington Barracks on April 20, 2011 in London, England. Soldiers involved in the Royal Wedding of Prince William and Catherine Middleton are preparing their ceremonial duties ahead of the day. (Photo by Oli Scarff/Getty Images)

Residents of the Korean port of Inchon surrender to American troops. (Photo by Bert Hardy/Getty Images). 1950

South Korean university students prepare for an establishment ceremony of the Reserve Officer Training Corps (ROTC) for female cadets at Sookmyung Women's University on December 10, 2010 in Seoul, South Korea. The South Korean defense ministry has agreed to admit women into it's college-based Reserve Officers' Training Program for the first time since the program began in 1963. (Photo by Chung Sung-Jun/Getty Images)