North Korean leader Kim Jong Un (front) stands on the conning tower of a submarine during his inspection of the Korean People's Army (KPA) Naval Unit 167 in this undated photo released by North Korea's Korean Central News Agency (KCNA) in Pyongyang June 16, 2014. (Photo by Reuters/KCNA)

North Korean leader Kim Jong Un smiles as he attends a flight training session by female fighter pilots Jo Kum Hyang and Rim Sol in this undated photo released by North Korea's Korean Central News Agency (KCNA) on June 22, 2015. (Photo by Reuters/KCNA/Antara Foto)

North Korean leader Kim Jong Un is hugged by children during his visit to Samjiyon County in this undated photo released by North Korea's Korean Central News Agency (KCNA) in Pyongyang November 28, 2016. (Photo by Reuters/KCNA)

Azalea, whose Korean name is “Dalle”, a 19-year-old female chimpanzee, lights a cigarette at the Central Zoo in Pyongyang, North Korea on Wednesday, October 19, 2016. According to officials at the newly renovated zoo, which has become a favorite leisure spot in the North Korean capital since it was re-opened in July, the chimpanzee smokes about a pack a day. They insist, however, that she doesn’t inhale. (Photo by Wong Maye-E/AP Photo)

South Korean girl group KARA arrive during the 21st High1 Seoul Music Awards at Olympic gymnasium on January 19, 2012 in Seoul, South Korea. (Photo by Chung Sung-Jun/Getty Images)

A woman poses for photographs with traditional side dish Kimchi during the Seoul Kimchi Festival in central Seoul, South Korea, November 4, 2016. Kimchi made with cabbage, other vegetables and chili sauce and kimchi is the most popular traditional food in Korea. (Photo by Kim Hong-Ji/Reuters)

A boy shouts after catching a trout during a trout catching contest in Hwacheon, South Korea, Saturday, January 6, 2018. The contest is part of an annual ice festival which draws over 1,000,000 visitors every year. (Photo by Ahn Young-joon/AP Photo)

A dog with a cherry blossom-shaped pin, is seen in the cherry blossom festival in Seoul, South Korea, Sunday, April 9, 2017. (Photo by Lee Jin-man/AP Photo)