An Afghan refugee girl shows her younger brother a calf in a slum on the outskirts of Islamabad, Pakistan, Friday, February 6, 2015. (Photo by Muhammed Muheisen/AP Photo)

A competitor walks on tightrope during a performance in Taizhou, Zhejiang Province, China, May 7, 2016. (Photo by Reuters/China Daily)

Liu Yang, China's first female astronaut, waves during a departure ceremony at Jiuquan Satellite Launch Center, on June 16, 2012. (Photo by Jason Lee/Reuters via The Atlantic)

Women pose for a picture at the entrance of the Carlton Hotel, in the government controlled area of Aleppo, Syria December 17, 2016. (Photo by Omar Sanadiki/Reuters)

A spectator cools herself at a water spraying fan at the Australian Open tennis championships in Melbourne, Australia, Tuesday, January 17, 2017. (Photo by Kin Cheung/AP Photo)

A member of the “Los Danzantes y Los Boteiros” folk group performs during the parade of the 10th International Festival of the Iberian Mask in Lisbon, Portugal May 9, 2015. The festival runs until next Sunday and about 690 masked people from Spain and Portugal are participating, according to organizers. (Photo by Rafael Marchante/Reuters)

A girl holds onto a pole as as she stands in floodwaters flowing from the swollen Bagmati River caused by heavy rainfall in Kathmandu, Nepal August 17, 2015. (Photo by Navesh Chitrakar/Reuters)

A participant, called a musher, races in the 33rd Aviemore Sled Dog Rally in Aviemore, Scotland January 23, 2016. The Siberian Husky Club of Britain is holding its annual sled dog rally over the weekend. (Photo by Russell Cheyne/Reuters)