U.S. Marines, left, and South Korean Marines, wearing blue headbands on their helmets, take positions after landing on the beach during the joint military combined amphibious exercise, called Ssangyong, part of the Key Resolve and Foal Eagle military exercises, in Pohang, South Korea, Saturday, March 12, 2016. North Korea said Saturday its military is ready to pre-emptively attack and “liberate” the South in its latest outburst against the annual joint military drills by the United States and South Korea. (Photo by Kim Jun-bum/Yonhap via AP Photo)

A participant in the Crazy Races extreme sports game competes in the cross-country obstacle race in Ufa, Russia on September 21, 2015. (Photo by TASS/Barcroft Media)

Tourists take pictures of straw figurines of traditional deities Shennong (R) and Zhang Wulang (L back) during China's National Day Holiday, in Xinhua county, Hunan province, October 4, 2015. (Photo by Reuters/China Daily)

An unidentified guest wears a hat with a lion at the Grand Palais which is transformed into a Chanel airport before German designer Karl Lagerfeld's Spring/Summer 2016 women's ready-to-wear collection for French fashion house Chanel during Fashion Week in Paris, France, October 6, 2015. (Photo by Benoit Tessier/Reuters)

Military school cadets take part in a ceremony commemorating the 56th anniversary of the death of Camilo Cienfuegos who, along with Fidel Castro and Che Guevara, was a chief commander of the Cuban revolution in Havana, Cuba on October 28, 2015. (Photo by Xinhua/REX Shutterstock)

A woman is consoled by her relative as she mourns after seeing her house getting burned during a fire that broke out in one of the houses and got spread in more adjoining houses, in a residential locality in Srinagar, November 21, 2016. (Photo by Danish Ismail/Reuters)

Rita Ora strips down to promote the new Tezenis lingerie range on December 7, 2016. The British singer, 26, shows off her curves in the latest campaign for the Italian brand. (Photo by Splash News/Tezenis)

Bronze whaler shark (Carcharhinus brachyurus), caught in traditional seine net and released by fisherman, Muizenberg beach, Cape Town, South Africa on October 11, 2016. Action shots have captured fishermen trying to free a potentially deadly Bronze Whaler shark who was caught in their nets. The incredible images show the eight-foot-long 500-pound predator lunging its mouth towards the fishermen who are desperately trying to pull it back into the safety of the sea by its tail. Eventually they succeeded. (Photo by Chris and Monique Fallows/NPL)