A leopard seal feeds Paul Nicklen a penguin. (Photo by Paul Nicklen/National Geographic). Antarctic Peninsula, 2011

In this photo taken October 16, 2012 and provided by Oracle Team USA, crew members of the capsized Oracle Team USA AC72 boat are rescued after being swept past the Golden Gate Bridge in San Francisco. The America's Cup champion syndicate is assessing the damage to its 72-foot catamaran, after it capsized and was swept by a strong current more than four miles past the Golden Gate Bridge before rescue boats could control it. (Photo by Guilain Grenier/Oracle Team USA/Associated Press)

Members of the Guard of Honor of the Presidential Regiment from Russia perform during the “Spasskaya Tower” international military music festival at Moscow's Red Square, Russia, September 10, 2015. The festival runs until 13 Sepember. (Photo by Maxim Shemetov/Reuters)

Romanian military doctors and medical students sit on a bus behind steamy windows before the National Day parade in Bucharest, Romania, Thursday, December 1, 2016. Military planes and helicopters flew over the Romanian capital Thursday as thousands turned out to celebrate the national day, marking the date when the country reunified with Transylvania in 1918. (Photo by Vadim Ghirda/AP Photo)

Students exercise in body training at Bishan Vocational Education Center in Chongqing, southwest China, January 13, 2016. These students were trained to be stewardesses of the high-speed train. (Photo by Xie Jie/Xinhua)

Two women pose as they drink real ale at the Great British Beer Festival in the Olympia exhibition centre on August 13, 2013 in London, England. The festival, which runs until August 17, 2013, has over 24 bars serving over 800 different beers, ciders and perries. (Photo by Oli Scarff)

Afghan men work in a small sweets factory in Kabul, Afghanistan January 5, 2017. (Photo by Mohammad Ismail/Reuters)

“This Way Up”. Photographic section portfolio, first prize. A Chinook CH-47 weapon systems operator prepares his aircraft during a training exercise in June 2018. (Photo bu SAC Ed Wright/RAF)