In this Thursday, June 14, 2018, file photo, students wear virtual reality goggles during a science class at Pyongyang Teachers' University, a teacher training college, in Pyongyang, North Korea. (Photo by Dita Alangkara/AP Photo)

North Korean youngsters sing and play accordions to entertain foreign visitors including United Nations Secretary General Kurt Waldheim, who visited Pyongyang, May 4, 1979. Visitors report music education in North Korea begins at an early age and is taken seriously by children and adults. (Photo by Peter Arnett/AP Photo)

A handout photo made available by the NASA shows the United Launch Alliance Delta IV Heavy rocket launches NASA's Parker Solar Probe to touch the Sun, from Launch Complex 37 at Cape Canaveral Air Force Station, Florida, USA, 12 August 2018. Parker Solar Probe is humanity’s first-ever mission into a part of the Sun’s atmosphere called the corona. Here it will directly explore solar processes that are key to understanding and forecasting space weather events that can impact life on Earth. (Photo by Bill Ingalls/EPA-EFE/NASA)

This unidentified teenager found Elvis Presley “too much” when he appeared at the Philadelphia Arena in Philadelphia, Pa., on April 6, 1957. (Photo by Bill Ingraham/AP Photo)

Women lie in the sun in Domino Park as high temperatures hit the region in Brooklyn, New York, U.S., August 29, 2018. (Photo by Andrew Kelly/Reuters)

Models kiss the back of another model, with a message on her back, during the grand finale of Lotus Make-up India Fashion Week based on “Rainbow” theme, an emblem for the LGBTQ community, in New Delhi, India, Sunday, October 14, 2018. According to Fashion Design Council of India, the “Rainbow” show, wherein 40 designers showcased their creations, was a tribute to mark the historic judgement by the Supreme Court of India which struck down a colonial-era law that made homosexual acts punishable by up to 10 years in prison. (Photo by Altaf Qadri/AP Photo)

A girl stretches next to a pram on the embankment of the Moskva river in Moscow on October 18, 2018. The European part of Russia enjoys an unusually warm weather for the season with temperatures reaching up to 22 degrees centigrade. (Photo by Mladen Antonov/AFP Photo)

Girls sits on a bench during summer at the Central Park in New York, United States, 2011. (Photo by An Rong Xu)