A rebel fighter carries his weapon as he moves through a hole in a wall in the old city of Aleppo near the frontline against forces loyal to Syria's President Bashar al-Assad December 28, 2014. (Photo by Jalal Al-Mamo/Reuters)

Residents carry a slaughtered pig with a bamboo pole as they walk home on a street, which was shut to traffic due to ice, in Leishan county, Guizhou province January 31, 2015. Blizzards and icy rain that lasted for several days at the end of January have disrupted traffic, collapsed houses and decimated crops in central Chinese provinces, Xinhua News Agency reported. (Photo by Reuters/Stringer)

A group of students sit on top of a bus at Kemusu street in Boyolali, Central Java of Indonesia, March 20, 2015 in this picture taken by Antara Foto. (Photo by Yusuf Nugroho/Reuters/Antara Foto)

Spectators cheer as the United Launch Alliance Delta 4-Heavy rocket, with NASA's Orion spacecraft mounted atop, lifts off from the Air Force Station, December 5, 2014, in Cape Canaveral, Fla. (Photo by Smiley N. Pool/AP Photo/Houston Chronicle)

Police officers stand near a fishing boat, the Carolina Queen III, as it rests in shallow water just off Rockaway Beach, Thursday, February 25, 2016, in the Queens borough of New York. Authorities say a Coast Guard vessel overturned while assisting the fishing boat that ran aground in an inlet off New York City. (Photo by Frank Franklin II/AP Photo)

A picture taken with slow shutter speed shows members of the group “The Kattfiller” from Attendorn taking part during the Norddeutsche Championship carnivalesque dance sport in Kassel (Hessen), Germany, 28 February 2016. About 1,100 qualified dancers show in different disciplines their skills. (Photo by Swen Pfoertner/EPA)

A woman transports fodder for her cattle on a bullock cart on the outskirts of Ajmer, Rajasthan, January 6, 2017. (Photo by Himanshu Sharma/Reuters)

Li Yuming, a local farmer who is interested in scientific invention, works on his unfinished miniature submarine “Xiaguang V” on the outskirts of Wuhan, capital of central China's Hubei province August 24, 2007. “Xiaguang V”, which is 3-metre long, 1.2-metre in height, has a maximum diving depth of 20 metres, and can hold two adults and one child at the same time. The submarine will be used for tour after safety test, local media said. (Photo by Reuters/Stringer)