Syrian rescue workers and residents help an injured woman following a reported air strike by government forces on the rebel-held neighbourhood of Haydariya in the northern city of Aleppo on April 10, 2016. (Photo by Thaer Mohammed/AFP Photo)

People walk during a polluted day in Shenyang, Liaoning province, March 31, 2016. (Photo by Reuters/Stringer)

Selfie picture shows Swiss pioneer Bertrand Piccard during the last leg of the round the world trip with Solar Impulse 2 over the Arab peninsula July 25, 2016. (Photo by Jean Revillard/Bertrand Piccard/Reuters/SI2)

An arrow-head discovered in 2006 by Archaeologists of the University of Cambridge Archaeological Unit, is displayed by one of the team uncovering Bronze Age wooden houses, preserved in silt, from a quarry near Peterborough, Britain, January 12, 2016. Archaeologists said on Tuesday they had discovered what were believed to be the best-preserved Bronze Age dwellings ever found in Britain, providing an extraordinary insight into prehistoric life from 3,000 years ago. (Photo by Peter Nicholls/Reuters)

This picture taken on March 1, 2016 shows a man running a mobile pig mating service and waiting outside a customer's home with his male pig in a cage pulled behind his motorcycle in the northern province of Bac Ninh. (Photo by Hoang Dinh Nam/AFP Photo)

Israeli soldiers of the Search and Rescue brigade take part in a training session in Ben Shemen forest, near the city of Modi'in May 23, 2016. (Photo by Amir Cohen/Reuters)

In this undated photo provided by LittleFriendsPhoto.com via Six Flags Discovery Kingdom, Kai, a 17-year-old male California sea lion at Six Flags Discovery Kingdom in Valejo, Calif. peers into the lens of photographer Seth Casteel, known for his “Underwater Dogs” photo series. ... (Photo by Seth Casteel/AP Photo/LittleFriendsPhoto.com via Six Flags Discovery Kingdom)

Palestinians hit injured Israeli settlers, center, detained by Palestinian villagers in a building under construction near the West Bank village of Qusra, southeast of the city of Nablus, Tuesday, January 7, 2014. Palestinians held more than a dozen Israeli settlers for about two hours Tuesday in retaliation for the latest in a string of settler attacks on villages in the area, witnesses said. The military said the chain of events apparently began after Israeli authorities removed an illegally built structure in Esh Kodesh, a rogue Israeli settlement in the area. In recent years, militant settlers have often responded to any attempts by the Israeli military to remove parts of dozens of rogue settlements, or outposts, by attacking Palestinians and their property. The tactic, begun in 2008, is known as “price tag”. (Photo by Nasser Ishtayeh/AP Photo)