Solar panels facing the sun from balconies of an apartment building in Mangyongdae District, Pyongyang, North Korea on April 21, 2015. (Photo by Reuters/Staff)





The top of the 105-storey Ryugyong Hotel in Pyongyang, North Korea on October 9, 2015. (Photo by Damir Sagolj/Reuters)





KCNA picture of the completed Mirae Scientists Street in Pyongyang, North Korea on October 21, 2015. (Photo by Reuters/KCNA)





A residential building in central Pyongyang, North Korea on October 9, 2015. (Photo by Damir Sagolj/Reuters)





The Monument to the Foundation of the Workers' Party in Pyongyang, North Korea on October 11, 2015. (Photo by Damir Sagolj/Reuters)





The Sci-Tech Complex in Pyongyang, North Korea on October 28, 2015. (Photo by Reuters/KCNA)





A view of the Sci-Tech Complex in Pyongyang, North Korea on October 28, 2015. (Photo by Reuters/KCNA)





Portraits of late North Korean leaders Kim Jong-il and Kim Il-sung (L) are lit at night in Pyongyang, July 24, 2013. (Photo by Jason Lee/Reuters)





Children attending the Congress of the Korean Children's Union (KCU) at the April 25 House of Culture in Pyongyang, North Korea on June 7, 2013. (Photo by Reuters/KCNA)





General view of the May Day Stadium in Pyongyang, North Korea on June 20, 2014. (Photo by Reuters/KCNA)





Statues of North Korea's founder Kim Il Sung and former leader Kim Jong Il at Mansudae hill in Pyongyang, North Korea on January 1, 2014. (Photo by Reuters/KCNA)





Fireworks explode in the sky over high rise buildings in Pyongyang, North Korea on December 31, 2014. (Photo by Reuters/KCNA)





A picture of North Korea's founder Kim Il-sung on a building in Pyongyang, North Korea on February 13, 2015. (Photo by Damir Sagolj/Reuters)





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





Soldiers walk in front of the Monument to the Foundation of the Workers' Party in Pyongyang, North Korea on April 16, 2017. (Photo by Damir Sagolj/Reuters)





A man walks in front of a replica of a Unha-3 rocket displayed in Pyongyang, North Korea on April 17, 2017. (Photo by Damir Sagolj/Reuters)





The newly built Ryugyong Kimchi Factory is seen in this undated photo released by North Korea's Korean Central News Agency (KCNA) on June 10, 2016. (Photo by Reuters/KCNA)





A member of staff looks from the balcony inside the Mangyongdae Children's Palace in central Pyongyang, North Korea on May 5, 2016. (Photo by Damir Sagolj/Reuters)





A general view shows a metro station in Pyongyang, North Korea on September 21, 2017. (Photo by Yuri Maltsev/Reuters)





People take part in the celebrations for the National Liberation Day in Pyongyang, North Korea on September 21, 2017. (Photo by Yuri Maltsev/Reuters)





Handout photo of North Korean leader Kim Jong Un providing field guidance to the Wonsan Baby Home and Orphanage in Pyongyang, North Korea on June 3, 2015. (Photo by Reuters/KCNA)