A runner competes in the Great Wall Marathon at the Huangyaguan Great Wall outside Beijing, China, May 18, 2019. (Photo by Thomas Peter/Reuters)

Rice seedling festival is a traditional folk festival in longji, guangxi, China on June 9, 2019, during grain in ear season. (Photo by Costfoto/Barcroft Media)

A boatman rests on his boat in the flooded Ganges river under the Shastri bridge at Daraganj Ghat, in Allahabad, India on August 22, 2019. (Photo by Sanjay Kanojia/AFP Photo)

Mae Zelinsky, left, and Betty O'Beda test ammunition on a .30 caliber rifle at a Remington Arms plant on April 30, 1943. Many women took over jobs that were left vacant when men went overseas to fight in World War II. (Photo by AP Photo)

France fan before the Russia 2018 World Cup Group C football match between Denmark and France at the Luzhniki Stadium in Moscow on June 26, 2018. (Photo by Axel Schmidt/Reuters)

The Invasion. A quiet street in Macau. Modernization around is quickly changing the city, as documented by Paul Tsui. (Photo by Paul Tsui/National Geographic Travel Photographer of the Year Contest)

A boy plays on the glass at Thailand's first skywalk in Bangkok, Thailand on November 18, 2018. (Photo by Soe Zeya Tun/Reuters)

A woman poses with a grenade launcher at a weapons exhibition during festivities marking Marines Day in St.Petersburg, Russia, Saturday, November 24, 2018. (Photo by Dmitri Lovetsky/AP Photo)