Valery Bystritskii, 10, gets a fellow student into a lock at Bunny's Gym in July 2015 in Winchester, Tennessee. (Photo by Mike Saliba/Barcroft USA)

Young girls attend a training session in MGFSO Olympic reserve school in Moscow on May 30, 2016. (Photo by Kirill Kudryavtsev/AFP Photo)

Children react after what activists said was shelling by forces loyal to Syria's President Bashar al-Assad near the Syrian Arab Red Crescent center in the Douma neighborhood of Damascus May 6, 2015. (Photo by Bassam Khabieh/Reuters)

A six-year-old acrobat performs on the opening of a tourist festival in Bozhou, Anhui province, China May 3, 2015. (Photo by Reuters/China Daily)

A girl bathes to cool off herself with water that is leaking from a broken pipe valve on a hot summer day on the outskirts of Ahmedabad, India, May 18, 2015. (Photo by Amit Dave/Reuters)

Lali carries balloons to sell on a beach in Mumbai, India, Sunday, October 11, 2015. The United Nations General Assembly marks October 11 as the International Day of the Girl Child, to recognize girls’ rights and the unique challenges girls face around the world. (Photo by Rafiq Maqbool/AP Photo)

Boys play with water as they celebrate Myanmar's New Year Water Festival of Thingyan in Yangon, April 13, 2016. (Photo by Soe Zeya Tun/Reuters)

Children play football in Bujumbura, Burundi on March 19, 2015. (Photo by Carl de Souza/AFP Photo)