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)

A woman aims a World War II machine gun at a military show during celebration of the Defenders of the Fatherland Day in St.Petersburg, Russia, Tuesday, February 23, 2016. The day, celebrated in Russia on February 23, honors the nation's military and is a nationwide holiday. (Photo by Dmitri Lovetsky/AP Photo)

A weeping South Vietnamese mother and her three children are shown on the deck of this amphibious command ship being plucked out of Saigon by U.S. Marine helicopters in Vietnam, April 29, 1975. (Photo by AP Photo)

Locals watch from the beach as waves hit an Indonesian tanker that ran aground near Narathiwat in southern Thailand December 19, 2014. The tanker loaded with palm oil, previously hijacked by its crew members and then seized by Thai authorities, was anchored some 400 meters from the beach but strong wind and waves broke it free, according to local media. (Photo by Surapan Boonthanom/Reuters)

A man dressed as Father Frost, Russian equivalent of Santa Claus, sits by the fire with a reindeer Yakut, marking winter solstice at the Royev Ruchey Park of Flora and Fauna in the Siberian Taiga wood in the suburbs of Krasnoyarsk, Russia, December 21, 2016. (Photo by Ilya Naymushin/Reuters)

Miss Utah Krissia Beatty competes in the swimsuit competition during the first night of preliminaries of Miss America at Boardwalk Hall in Atlantic City, New Jersey, September 8, 2015. (Photo by Mark Makela/Reuters)

Elfyn Evans of Great Britain and Daniel Barritt of Great Britain compete in their M-Sport WRT Ford Fiesta RS WRC during Day One of the WRC Australia on September 11, 2015 in Coffs Harbour, Australia. (Photo by Massimo Bettiol/Getty Images)

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)