South Korean special warfare command soldiers participate in winter military training exercise on January 11, 2012 in Pyeongchang-gun, South Korea. The South Korean troops train in temperatures below -20 degrees celsius to defend the country against any possible attacks from North Korea. (Photo by Chung Sung-Jun/Getty Images)

Bottlenose dolphins leap off the Southern California coast on January 30, 2012 near Dana Point, California. A coalition that includes Native American tribes, Earthjustice and the Natural Resources Defense Council is on the National Marine Fisheries Service for more protection for dolphins, whales, and other migrating marine animals from the use of sonar in training by the US Navy on the West Coast. (Photo by David McNew/Getty Images)

Emergency personnel respond to the scene of a train derailment in Santiago de Compostela, Spain, on Wednesday, July 24, 2013. A train derailed in northwestern Spain on Wednesday night, toppling passenger cars on their sides and leaving at least one torn open as smoke rose into the air. Dozens were feared dead, with possibly even more injured. (Photo by Antonio Hernandez/AP Photo/El correo Gallego)

Romanian soldiers take part in a joint military exercise with NATO members, called “Agile Spirit 2015” at the Vaziani military base outside Tbilisi, Georgia, July 21, 2015. Georgian soldiers along with U.S. marines and platoon-size units from Bulgaria, Latvia, Lithuania and Romania are taking part in the exercises at the Vaziani military base outside Tbilisi. (Photo by David Mdzinarishvili/Reuters)

“A topless women's rights activist hacked down a Christian cross in the Ukrainian capital Kiev with a chain saw on Friday in protest at the prosecution of the Russian feminist punk band, p*ssy Riot”. – Reuters. (Photo by FEMEN)

An animatronic dragon performs during the launch of How To Train Your Dragon Arena Spectacular at a Dreamworks and Global Creatures media call on August 8, 2011 in Melbourne, Australia. (Photo by Quinn Rooney/Getty Images)

A performer poses with “The Gronkle” and “Deadly Nadder” at the How to Train Your Dragon Media Call at Fox Studios on November 29, 2011 in Sydney, Australia. The “How to Train Your Dragon Arena Spectacular” world premiere will take place in Australia in March 2012. (Photo by Brendon Thorne/Getty Images)

A security exercise takes place along the River Thames on January 19, 2012 in London, England. The exercise including around 44 police officers, 94 military personnel, 15 boats and a Royal Navy Lynx helicopter was conducted by both the Metropolitan Police and the Royal Marines and designed to test their joint capability ahead of the 2012 London Olympic Games. (Photo by Dan Kitwood/Getty Images)