A man from Dinka tribe holds his AK-47 rifle in front of cows in a Dinka cattle herders camp near Rumbek, capital of the Lakes State in central South Sudan December 14, 2013. (Photo by Goran Tomasevic/Reuters)

Members of the Royal Navy respond to a simulated fire in a Vanguard-class submarine control room training facility at Clyde naval base in Faslane, Scotland on January 21, 2016. (Photo by Photograph: Danny Lawson/PA Wire)

Indonesian residents look at the Mount Sinabung volcano as it spews volcanic ash near the Tiga Pancur village in Karo, North Sumatra on August 3, 2016. Volcanic eruptions in Indonesia in recent days have forced the closure of two airports and disrupted some flights to the holiday island of Bali, officials said August 3. Mount Sinabung, a volcano on the western island of Sumatra which has been rumbling for some time, also erupted violently on August 2, although its ash clouds did not disrupt any flights. (Photo by Y.T. Haryono/AFP Photo)

Actors dressed as a “Yeti” attend a promotional event for Travel Channel's “Expedition Unknown: Hunt for the Yeti” in Manhattan, New York City, U.S., October 4, 2016. (Photo by Brendan McDermid/Reuters)

Models on the catwalk Yeezy: Season 4 show, Spring Summer 2017, New York Fashion Week, USA on September 7, 2016. (Photo by Your Name/BFA/Rex Features/Shutterstock)

Cast member Shu Qi poses during a photocall for the film “The Assassin” (Nie yin niang) in competition at the 68th Cannes Film Festival in Cannes, southern France, May 21, 2015. (Photo by Eric Gaillard/Reuters)

A man impersonating Kim Jong-un gestures during the athletics at the Rio 2016 Olympic Games at the Olympic Stadium in Rio de Janeiro on August 18, 2016. (Photo by Johannes Eisele/AFP Photo)

Charli XCX arrives for the 30th Annual ARIA Awards 2016 at The Star on November 23, 2016 in Sydney, Australia. (Photo by Brendon Thorne/Getty Images)