A view of a Van Gogh-inspired hot air balloon being inflated during the Philippine International Hot Air Balloon Fiesta at Clark Freeport Zone in Pampanga province, north of Manila February 12, 2015. According to the organizer, a total of 32 hot air balloons are part of the four-day event. (Photo by Erik De Castro/Reuters)

Hot air balloons take part in the 38th International Balloon Festival of Chateau-d'oex, Switzerland, 23 January 2016. For nine days balloonists from 15 countries take part in the ballooning event in the Swiss mountain resort famous for ideal flight conditions due to an exceptional microclimate. The festival takes place from 23 to 31 January. (Photo by Cyril Zingaro/EPA)

South Korean youths dance to electronic music during the Ultra Music Festival Korea at Olympic Stadium on June 10, 2016 in Seoul, South Korea. (Photo by Jean Chung/Getty Images)

Girls enjoy nice weather at a park in front of the Pothonggang Department Store in central Pyongyang October 11, 2015. (Photo by Damir Sagolj/Reuters)

North Korean soldiers wave along the Yalu River, near the North Korean town of Sinuiju, opposite to the Chinese border city of Dandong October 7, 2014. (Photo by Jacky Chen/Reuters)

A man pulls a cart with collapsed cardboard boxes past boutiques in the Sinchon district in Seoul, May 5, 2015. (Photo by Thomas Peter/Reuters)

A soldier walks on the bank of the river in central Pyongyang, North Korea on April 16, 2017. (Photo by Damir Sagolj/Reuters)

A woman travels on a train stopping at a subway station visited by foreign reporters in central Pyongyang, North Korea on April 14, 2017. (Photo by Damir Sagolj/Reuters)