An elephant “kisses” a visitor during a show at an elephant training school in Xishuangbanna, Yunnan province, April 18, 2015. Some 16 elephants live at the school and give four 30-minute performances everyday for visitors. (Photo by Wong Campion/Reuters)

Chacha, the male chimp, screams at a worker in Sendai, northern Japan, Thursday, April 14, 2016 after fleeing from a zoo. The chimpangzee tried desperately to avoid being captured by climbing an electric pole. Chacha was on the loose nearly two hours Thursday after it disappeared from the Yagiyama Zoological Park in Sendai, the city that's hosting finance ministers from the Group of Seven industrialized nations in May. (Photo by Kyodo News via AP Photo)

“People and Space”. Winner: Wanderer in Patagonia by Yuri Zvezdny (Russia) A lone stargazer stares up at the stars of our galaxy, the Milky Way, as they stretch across the night sky over the glacier “White Stones” (Piedras Blancas) in the Los Glaciares National Park, Argentina. El Chaltén, Santa Cruz Province, Argentina, 27 September 2016 iOptron Sky-Tracker mount, Sony A7S camera, 18 mm f/2.8 lens, ISO 5000, 30-second exposure Wanderer in Patagonia. (Photo by Yuri Zvezdny/Insight Astronomy Photographer of the Year 2017)

Festival-goers wash on Shipyard Island, the venue of the 24th Sziget (Island) Festival in Northern Budapest, Hungary, 15 August 2016. The venue, one of the biggest cultural events of Europe, offers art exhibitions, theatrical and circus performances and above all music concerts from 10 to 17 August. (Photo by Szabó Gábor/Origo.hu)

A young Free Syrian Army fighter holds a rifle in Haresta neighbourhood of Damascus January 16, 2013. (Photo by Goran Tomasevic/Reuters)

A tourist watches as the moon passing in front of the sun as it approaches a full solar eclipse in the northern Australian city of Cairns November 14, 2012. (Photo by Tim Wimborne/Reuters)

A woman dancing on the Sphinx. A pyramid can be seen in the background. (Photo by Fox Photos/Getty Images). 1928

A recruitment drive during the First World War at Trafalgar Square, London. (Photo by Central Press/Getty Images)