Lightning from a tornadic thunderstorm passing over Clearwater, Kansas strikes at an open field May 19, 2013. A massive storm front swept north through the central United States on Sunday, hammering the region with fist-sized hail, blinding rain and tornadoes, including a half-mile wide twister that struck near Oklahoma City. News reports said at least one person had died. (Photo by Gene Blevins/Reuters)

Turks stand in a silent protest in Kugulu Park in Ankara, Turkey, Wednesday, June 19, 2013. After weeks of sometimes-violent confrontation with police, Turkish protesters have found a new form of resistance: standing still and silent. The banner with an image of Turkey's founder Kemal Ataturk reads: “Which crazy person thinks they can put me in chains”. (Photo by Burhan Ozbilic/AP Photoi)

Grey seal pup “Nikolaus” licks a window at the seal enclosure in Friedrichskoog, Germany, 19 December 2014. The pup was abandoned by his mother and would not have a chance at survival without human help. Nikolaus will be fed at the enclosure for two to three months until he has reached the minimum weight of 45 kilograms for being released. (Photo by Daniel Reinhardt/EPA)

Men stand at the top of a traffic lights post as they attend a rally to protest against satirical cartoons of prophet Mohammad, in Grozny, Chechnya January 19, 2015. Tens of thousands of people staged the rally on Monday in Chechnya against French magazine Charlie Hebdo's cartoons of the prophet, which the predominantly Muslim region's leader denounced as “vulgar and immoral”. The posters read, “Mohammad”. (Photo by Eduard Korniyenko/Reuters)

Miss USA, Olivia Culpo, appears on stage during the Miss Universe Pageant at Planet Hollywood in Las Vegas, Nevada on December 19, 2012. Olivia Culpo was crowned Miss Universe 2012, beating out beauties from around the world to claim the coveted title. The title of first runner-up title went to the contestant from the Philippines, Janine Tugonon. (Photo by Joe Klamar/AFP Photo)

The Hubble Space Telescope is shown following its release from the space shuttle Discovery Wednesday, February 19, 1997. The Hubble Space Telescope, one of NASA'S crowning glories, marks its 25th anniversary on Friday, April 24, 2015. With more than 1 million observations, including those of the farthest and oldest galaxies ever beholden by humanity, no man-made satellite has touched as many minds or hearts as Hubble. (Photo by AP Photo/NASA)

Growing cities, overuse of fertilizers and factory wastewater have degraded China's water supplies to the extent that half the nation's rivers and lakes are severely polluted. China aims to spend $850 billion to improve filthy water supplies over the next decade, but even such huge outlays may do little to reverse damage caused by decades of pollution and overuse in Beijing's push for rapid economic growth. Photo: Fishermen row a boat in the algae-filled Chaohu Lake in Hefei, Anhui province, June 19, 2009. (Photo by Jianan Yu/Reuters)

Pierre Thivillon (R), director of the zoological park of Saint-Martin-La-Plaine and his wife Eliane look at Digit, an 18-year-old female gorilla, on August 19, 2016, in Saint-Martin-La-Plaine between Lyon and Saint-Etienne, southeastern France. The zoological park of Saint-Martin-La-Plaine is a shelter for beasts seized by the justice. (Photo by Philippe Desmazes/AFP Photo)