Migrants rush as they try to get on a train heading to the border with Serbia at the train station of Gevgelija, on the Macedonian-Greek border, on August 9, 2015. Non-EU Serbia's frontier with Hungary, which is in the bloc's passport-free Schengen zone, has become a major crossing point for the huge numbers of migrants entering the EU. (Photo by Dimitar Dilkoff/AFP Photo)

Firefighters watch as an air tanker drops retardant while battling the Ferguson fire in the Stanislaus National Forest, near Yosemite National Park, California on July 21, 2018. A fire that claimed the life of one firefighter and injured two others near California's Yosemite national park has almost doubled in size in three days, authorities said Friday. (Photo by Noah Berger/AFP Photo)

This female orangutan was born at the zoo in the German capital of Berlin. German online users have fallen in love with Berlin Zoo's most recent addition – this newborn orangutan. The female orangutan was born in the early hours of 12th January at the zoo in the German capital of Berlin and weighed a tiny 1.8 kilograms, normally regarded as small for an orangutan baby but nevertheless the infant is healthy and strong. (Photo by Europics/Zoo Berlin)

A devotee takes a holy bath at the Balaju Baise Dhara (22 water spouts) during the Baishak Asnan festival in Kathmandu April 4, 2015. Devotees believe that the water from these stone spouts, which is collected from the catchment area of the Nagarjun forest behind the spouts, will cure pains and skin diseases. (Photo by Navesh Chitrakar/Reuters)

A performer wearing costumes walk on stilts before a show during a lantern fair at the beginning of Chinese Lunar New Year, in Xi'an, Shaanxi province, February 11, 2016. (Photo by Reuters/Stringer)

Riot police arrest an anti-government protester in Ouagadougou, capital of Burkina Faso, October 30, 2014. Thousands of protesters marched on Burkina Faso's presidential palace after burning the parliament building and ransacking state television offices on Thursday, forcing President Blaise Compaore to scrap a plan to extend his 27-year rule. Emergency services said at least three protesters were shot dead and several others wounded by security forces when the crowd tried to storm the home of Compaore's brother. Security forces also fired live rounds and tear gas at protesters near the presidency in the Ouaga 2000 neighborhood. (Photo by Joe Penney/Reuters)

A prototype battery-powered plane, called Greased Lightning or GL-10 is pictured flying at NASA's Langley Research Center in this undated handout photo obtained by Reuters May 1, 2015. The plane, which has 10 engines and can take off like a helicopter and fly efficiently like an aircraft, is currently in the design and testing phase. (Photo by Reuters/NASA)

Local villagers ride a local coal powered steam train on March 27, 2015 at a station in the town of Shixi , Sichuan Province, in Southern China. While China boasts the world's most extensive high-speed rail infrastructure with over 16,000 kilometers of track, the Shixi-Bagou railway is still a primary connection for local villagers between towns and is kept alive by tourist cars carrying passengers for ten times the price. The rail line came into service in the late 1950s and the train was initially used to transport coal from a now-shuttered mine before passenger carriages were added. (Photo by Kevin Frayer/Getty Images)