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)

Syrian refugee boys play with toy guns at Eminonu district in Istanbul, Turkey, 08 January 2019. (Photo by Sedat Suna/EPA/EFE)

An Iraqi shi'ite muslim girl places a copy of the Koran on her head during the holy month of Ramadan at the Imam Ali Shrine, in the holy city of Najaf, Iraq on May 28, 2019. (Photo by Alaa Al-Marjani/Reuters)

An official (R) measures the size of a whale shark (Rhincodon typus) carcass on the shore of Teluk Betung beach in West Sumatra, Indonesia, 08 October 2019. The dead whale shark washed ashore at Teluk Betung beach on 07 October 2019. (Photo by Rajo Batuah/EPA/EFE)

Police officers hold a revolver as they offer prayers to their weapons as part of a ritual at their headquarters on the occasion of Dussehra, or Vijaya Dashami, festival in Ahmedabad, India, October 8, 2019. (Photo by Amit Dave/Reuters)

U.S. Air Force wounded warrior, Capt. Sarah Evans, jumps rope in a gym in San Antonio, Texas. Evans was diagnosed with cancer while deployed to Afghanistan and was medically evacuated back to the United States where her leg was amputated. (Photo by Master Sgt. Jeffrey Allen/U.S. Air Force)

“Misty Morning”. Every morning, people expect sunny weather. Photo location: Bali, Indonesia. (Photo and caption by Henry Adam/National Geographic Photo Contest)

Students receive a group punishment during a military-style close-order drill class at the Qide Education Center in Beijing February 19, 2014. The Qide Education Center is a military-style boot camp which offers treatment for internet addiction. As growing numbers of young people in China immerse themselves in the cyber world, spending hours playing games online, worried parents are increasingly turning to boot camps to crush addiction. Military-style boot camps, designed to wean young people off their addiction to the internet, number as many as 250 in China alone. (Photo by Kim Kyung-Hoon/Reuters)