“The Challenge!” Young boy relishes in a game of tug of war before school. Photo location: Lake Titicaca, Peru. (Photo and caption by Paul Heyman/National Geographic Photo Contest)

A boy performs a masked dance as he participates in a parade during the National Encounter of Mask festival in Barva de Heredia October 30, 2015. (Photo by Juan Carlos Ulate/Reuters)

A boy covers his head with fallen leaves as he enjoys a stroll with his family in a park in downtown Frankfurt, Germany, November 6, 2016. (Photo by Kai Pfaffenbach/Reuters)

Children admire the work “Little Lost Boy” by Australian artist Paul Trefry is seen on Tamarama Beach as part of the Sculptures By The Sea outdoor art exhibition on November 10, 2009 in Sydney, Australia. (Photo by Ryan Pierse/Getty Images)

Blood drips down from the face of a Shi'ite Muslim boy after practicing a self-flagellation ritual during a religious procession of the Ashura mourning period on December 6, 2011 in New Delhi, India. (Photo by Daniel Berehulak/Getty Images)

A Palestinian boy carries dates from palm trees during harvest season in southern Gaza September 25, 2016. (Photo by Ibraheem Abu Mustafa/Reuters)

Boys play with a ball in front of oilfields burned by Islamic State fighters in Qayyara, south of Mosul, Iraq November 23, 2016. (Photo by Goran Tomasevic/Reuters)

A boy carries sugar cane through a farm on the outskirt of Zaria in Nigeria's northern state of Kaduna November 15, 2016. (Photo by Akintunde Akinleye/Reuters)