A member of the Eton public school O.T.C. (Officers Training Corps) practising shouting out orders during a training session, 20th January 1940. (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)

A rag-and-bone woman stands next to carriages of a coal train outside a coal mine of the state-owned Longmay Group on the outskirts of Jixi, in Heilongjiang province, China, October 22, 2015. (Photo by Jason Lee/Reuters)

In this Monday, October 5, 2015 photo, a thick blanket of early morning fog partially shrouds the skyscrapers of the Marina and Jumeirah Lake Towers districts of Dubai, United Arab Emirates. Dubai's rapid transformation from a desert outpost into one of the world's most architecturally stunning cities is mapped out in the Marina. Where just 15 years ago there was empty, flat land, today a bustling neighborhood thrives centered around a canal and an impressive skyline that pierces through the clouds. (Photo by Kamran Jebreili/AP Photo)

A girl performs martial arts during a function to mark International Women's Day at a school in Hyderabad, India, on March 7, 2014. (Photo by Mahesh Kumar A./Associated Press)

People watch police destroy confiscated illegal firecrackers in Shenyang, Liaoning province, China, January 29, 2016. (Photo by Reuters/Stringer)

A reveller (R), dressed as “Diablos de Luzon” (Luzon Devils), stands next to a person dressed as a “Mascaritas” during carnival celebrations in the village of Luzon, Spain, February 6, 2016. The “Diablos” cover themselves in a mixture of soot and oil and adorn their heads with black-stained bull horns as they parade throughout the village with cowbells clanging around their waists to expel the evil spirits. (Photo by Sergio Perez/Reuters)

A child plays with a plastic badminton racket in the old quarters of Delhi, India, March 3, 2016. (Photo by Anindito Mukherjee/Reuters)