North Korean leader Kim Jong Un, his wife Ri Sol Ju and Song Tao, head of the International Department of Communist Party of China (CPC) Central Committee, applaud with ballet dancers in this undated photo released by North Korea's Korean Central News Agency (KCNA) in Pyongyang April 17, 2018. (Photo by Reuters/KCNA)

A family wearing traditional Japanese clothing posed for a photograph during spring season in one of the garden in Kiyomizu dera, Kyoto prefecture, Japan on March 30, 2018. (Photo by Richard Atrero de Guzman/NurPhoto via Getty Images)

Prince Philip, Duke of Edinburgh practicing his bicycle polo technique, Windsor Great Park, Berkshire, 1964. (Photo by Norman Potter/Daily Express/Hulton Archive/Getty Images)

Evangelia Platanioti of Greece competes in the Solo Technical Routine at the Glasgow 2018 European Synchronised Swimming Championships, Glasgow, Britain, 06 August 2018. (Photo by Neil Hall/EPA/EFE)

An artist dressed as demon King Ravana reacts as he participates in Vijaya Dashmi, or Dussehra festival celebrations in Chandigarh, India October 19, 2018. (Photo by Ajay Verma/Reuters)

Workers carry a metal sheet at a dockyard in Dhaka, Bangladesh, December 5, 2018. (Photo by Mohammad Ponir Hossain/Reuters)

These are the stunning pictures of the night sky brilliantly capturing the lights and colors of the Milky Way glistening over desert landscapes. Taken in various locations across Australia and the United States from the Grand Canyon to the Coral Sea, the pictures perfectly show the bright lights of the starry skies. Here: Bisit Badlands, New Mexico. (Photo by Wayne Pinkston/Caters News)

Women practice yoga during a performance on a glass bridge at the Shiniuzhai National Geo-park in Pingjiang county, Hunan province, China, November 5, 2015. About hundred yoga fans put on the show to promote the concept of green life and the idea of harmony between human and nature on Thursday, according to local media. (Photo by Reuters/China Daily)