Tourists take photos from a panoramic viewing deck on Victoria Peak in Hong Kong, China, 26 January 2019. Hong Kong has been ranked the world's freest economy by the Heritage Foundation, a conservative research and educational institution based in Washington, for the 25th consecutive year, but the researchers also said the judiciary had become less effective. (Photo by Jerome Favre/EPA/EFE)

Soldiers on exercise in Kenya. The image, by Sergeant Dek Traylor, is among the section winners in the UK Army Photographic Competition 2018. (Photo by Sergeant Dek Traylor/PA Wire Press Association)

An Indonesian jockey rides two bulls with a cart during a traditional sport bull race locally called “pacu jawi” in Pariangan of Tanah Datar regency in West Sumatra on December 1, 2018. (Photo by Adek Berry/AFP Photo)

Festival goers participate in a dance class on embracing kinetic intimacy in the dance shala a the Oregon Eclipse Festival, August 20, 2017, at Big Summit Prairie ranch in Oregon' s Ochoco National Forest near the city of Mitchell ahead of the total solar eclipse on August 21, 2017. (Photo by Robyn Beck/AFP Photo)

Syrian refugee and Olympic swimmer Yusra Mardini is pictured during a training session in a pool at the Olympic park in Berlin, Germany on April 26, 2018. (Photo by Fabrizio Bensch/Reuters)

Iraqi firefighters try to stop the fire of burning oil wells in Kirkuk, northern Iraq, 02 June 2016. Two Khabbaz oil field wells in Kirkuk Province, northern Iraq, exploded by suspected insurgents, a security official said. (Photo by EPA/Stringer)

Angel Hall, 22, (C) and Bri Artis, 21, (R) dance in a silent disco on the fourth and final day of the Firefly Music Festival in Dover, Delaware on June 17, 2018. (Photo by Mark Makela/Reuters)

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)