Members of the American Civil War Society take part in a mock battle in the grounds of Cusworth Hall, South Yorkshire on July 2, 2011 in Doncaster, United Kingdom. Enthusiasts from all walks of life are taking part in re-enacting scenes from the American Civil War and in 'living history' events which are as authentic as possible. (Photo by Christopher Furlong/Getty Images)

Encyclopedia Britannica editions are seen at the New York Public Library on March 14, 2012 in New York City. Encyclopedia Britannica announced it will be ceasing its print edition of reference books for the first time in its 244-year history to focus solely on digital versions. (Photo by Mario Tama/Getty Images)

Boys eat at a rubbish dump where they are collecting recyclable waste outside Yemen's Red Sea port city of Houdieda January 20, 2016. (Photo by Abduljabbar Zeyad/Reuters)

A boy works on a car in Babi Kouakou's car repair garage in Bouake, Ivory Coast February 9, 2016. Babi specialises in restoring old cars. (Photo by Thierry Gouegnon/Reuters)

Boys ride a motorbike on their way back home after taking a bath in a canal at Chachura village, in Uttar Pradesh April 4, 2012. (Photo by Parivartan Sharma/Reuters)

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)

A boy runs past one of the exhibits during the Dinosaurs exhibition in Belgrade, Serbia, Thursday, August 21, 2014. “Dino Park” has opened at Belgrade's Kalemegdan Fortress. (Photo by Darko Vojinovic/AP Photo)