Dancers prepare before a performance in the backstage area of the Buick exhibition during the “Auto China 2014” Beijing International Automotive Exhibition in Beijing on April 21, 2014. Leading automakers have gathered in Beijing for the kickoff of China's biggest car show, but lackluster growth and environmental restrictions in the world's largest car market have thrown uncertainty into the mix. (Photo by AFP Photo)

Children surround a man, left, that fell down while walking on a street suspected of having contracted the Ebola virus in the city of Monrovia, Liberia, Tuesday, August 19, 2014. The World Health Organization says the outbreak has killed more than 1,200 people, while authorities struggle to contain its spread and treat the sick. (Photo by Abbas Dulleh/AP Photo)

A picture released by the North Korean Central News Agency (KCNA) shows Kim Jong-un convening an urgent operation meeting at 0:30 am on March 29, 2013 at an undisclosed location, in which he ordered strategic rocket forces to be on standby to strike US and South Korean targets at any time. (Photo by KCNA via EPA)

A huge wave crashes against Castlerock pier as professional surfer Al Mennie waits on a break in the swell on December 22, 2016 in Coleraine, Northern Ireland. Storm Barbara is expected to cause major travel disruption when it hits northern parts of the UK later with 90mph winds predicted. The Met Office has issued an amber warning with the worst effects of the storm expected on Friday and Saturday. (Photo by Charles McQuillan/Getty Images)

Battle-weary American troops withdraw from Yong San in Korea. (Photo by Keystone/Getty Images). 1950

Riot police stood by the gates of parliament in Nairobi, Kenya, Tuesday, May 14, 2013, during a demonstration against members of parliament who demanded higher wages. Demonstrators released two dozen piglets and poured blood on the pavement to protest the demands for a wage hike. (Photo by Carl de Souza/AFP Photo)

AP photographer Anja Niedringhaus laughs as she attends a swimming event at the 2004 Olympic Games in Athens, August 21, 2004. Niedringhaus, a veteran Associated Press photographer who had covered wars around the world was shot dead and another reporter was wounded on April 4, 2014 when an Afghan policeman opened fire on them in eastern Afghanistan, the news agency said. (Photo by Reuters/Staff)

Children are engulfed by foam during the Bubble Show event in Beijing, China, Sunday, June 26, 2016. Thousands of residents enjoy colored foam churned out by machines along a running track at the event designed for children and parents' interaction. (Photo by Ng Han Guan/AP Photo)