South Korean soldiers participate in a winter river crossing operation in preparation for a possible North Korean attack on February 8, 2012 in Yeoju, South Korea. The Korean peninsula is the world's last Cold War frontier as stalinist North Korea and pro-western South Korea have been technically at war since the 1950-53 conflict. (Photo by Chung Sung-Jun/Getty Images)

A soldier eats ice cream as she visits a zoo in Pyongyang, North Korea, September 12, 2018. (Photo by Danish Siddiqui/Reuters)

People carry the body of a man they uncovered from under the rubble of houses destroyed by Saudi airstrikes in the old city of Sanaa, Yemen, Friday, June 12, 2015. (AP Photo/Hani Mohammed)

A subway worker walks away after a train departed the station in central Pyongyang, North Korea May 7, 2016. (Photo by Damir Sagolj/Reuters)

Two railway workers chat in front of a flower mural inside a subway station visited by foreign reporters during a government organised tour in Pyongyang, North Korea October 9, 2015. (Photo by Damir Sagolj/Reuters)

Soldiers pose for a photo during the flower exhibition marking the 105th birth anniversary of the country's founding father, Kim Il Sung in Pyongyang, North Korea April 16, 2017. (Photo by Damir Sagolj/Reuters)

A pedestrian battles against gale force winds in Adelaide Street West next to the promenade in Blackpool on December 28, 2011 in Blackpool, England. (Photo by Christopher Furlong/Getty Images)