An Indian Runner duck searches for food on a snow-covered meadow in Aitrang, southern Germany, Wednesday. April 19, 2017. (Photo by Karl-Josef Hildenbrand/DPA via AP Photo)

A crocodile at a zoo in the southern Taiwan city of Kaohsiung holds the forearm of a zoo veterinarian in its teeth, April 2007. Surgeons in Taiwan have reattached a vet's arm, after it was bitten off by a crocodile as he tried to give it an anaesthetic injection. His attacker is one of a pair of Nile crocodiles kept at Shoushan zoo. Nile crocodiles are known to be man-eaters, but are also listed as an endangered species. (Photo by Frank Lin/Reuters)

Children, wearing red neckerchiefs, a symbol of the Pioneer Organization, salute during a ceremony for the inauguration of 18 new members at a local school in the southern settlement of Kazminskoye in Stavropol region, Russia, November 19, 2015. Early pro-communist youth movements, which appeared in Russia after the 1917 Bolshevik revolution, were reformed into the Pioneer Organization of the Soviet Union. While the organization lost its dominance among students in post-Soviet Russia, some educational institutions and families still carry on this tradition. (Photo by Eduard Korniyenko/Reuters)

A general view showing the shipwrecked cruise ship Costa Concordia in an upright position after the salvage operations in Giglio island, Italy, 17 September 2013. Salvage crews pulled off a major engineering feat when they straightened the listed Costa Concordia cruise ship from the rocks it had been wedged against for the past 20 months. The delicate operation took 19 hours and was completed at 4 am (0200 GMT). The vessel ran aground near the island of Giglio, in Tuscany, in an accident that made world-wide news. (Photo by Angelo Carconi/EPA)

Models promote a condom brand at the first Shenzhen s*x Culture Festival on September 21, 2007 in Shenzhen of Guangdong Province, China. The festival aims to increase awareness about reproductive health and popularise s*x education. (Photo by China Photos/Getty Images)

Bride Yulia Tagil sits on the backseat of a bike as she arrives for her alternative wedding ceremony on a square in Tel Aviv July 25, 2010. The alternative wedding ceremony was intended to demonstrate against the current situation in Israel, where the only way for Jews to get married by law is through the Chief Rabbinate. (Photo by Nir Elias/Reuters)

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)

Thailand's King Bhumibol Adulyadej in serious portrait January 01, 1960. Thailand's Royal Palace said on Thursday, October 13, 2016, that Thailand's King Bhumibol Adulyadej, the world's longest-reigning monarch, has died at age 88. (Photo by John Dominis/The LIFE Picture Collection/Getty Images)