Russian soldiers write home while serving on the Eastern Front during World War I, circa 1915. (Photo by Hulton Archive/Getty Images)

A student attending a winter military camp reacts during a training session in Ansan, south of Seoul January 3, 2013. Hundreds of students between 11 and 17 years old attend winter boot camp training courses every year. The winter courses range from 4 to 14 days at the Blue Dragon Camp run by retired marines, which also offers summer boot camp for students. (Photo by Kim Hong-Ji/Reuters)

Students take part in a fashion and design entrance examination at Hubei Institute of fine Arts on February 28, 2011 in Wuhan, Hubei Province of China. 202 students took part in the exam and only 24, (10 percent) of them will be enrolled in Hubei Institute of fine Arts. (Photo by ChinaFotoPress/Getty Images). WUHAN, CHINA – FEBRUARY 28

A protestor gestures during clashes with police during protests against planned fuel price hikes on March 27, 2012 in Jakarta, Indonesia. Thousands of Indonesians students in big cities all over the county gathered to protest the governments plans to increase the price of subsidized fuel by 30 percent. The Indonesian parliament is currently debating the fuel hikes which would go into effect March 25, 2012 if approved. (Photo by Ulet Ifansasti/Getty Images)

Students from St Andrew's University indulge in a tradition of covering themselves with foam to honour the “academic family” on October 20, 2014, in St Andrews, Scotland. Every November the “raisin weekend” which is held in the university's Lower College Lawn, is celebrated and a gift of raisins (now foam) is traditionally given by first year students to their elders as a thank you for their guidance and in exchange they receive a receipt in Latin. (Photo by Jeff J. Mitchell/Getty Images)

A German Air Force Officer sits astride a dead boar outside a house where he is stationed near the Western Front, in this 1918 handout picture. This picture is part of a previously unpublished set of World War One (WWI) images from a private collection. The pictures offer an unusual view of varied and contrasting aspects of the conflict, from high tech artillery to mobile pigeon lofts, and from officers partying in their headquarters to the grim reality of life and death in the trenches. The year 2014 marks the centenary of the start of the war. (Photo by Reuters/Archive of Modern Conflict London)

Edward, Prince of Wales (1840–1910), later King Edward VII, stands over the carcass of a wild Chillingham bull, shot by himself during a visit to Chillingham Castle, Northumberland, circa 1879. (Photo by Hulton Archive/Getty Images)

A protester uses molotov cocktails against riot police during May Day protests on May 1, 2010 in Athens, Greece. (Photo by Milos Bicanski /Getty Images)