Revellers take part in the the 70th Annual Columbus Day Parade in New York, October 13, 2014. (Photo by Eduardo Munoz/Reuters)

Participants wear traditional clogs as shepherds lead their sheep through the center of Madrid, October 28, 2012. (Photo by Andres Kudacki/Associated Press)

This picture taken on September 3, 2014 shows a man taking pictures of floodwater released from the Three Gorges Dam, a gigantic hydropower project on the Yangtze river, in Yichang, central China's Hubei province, after heavy downpours in the upper reaches of the dam caused the highest flood peak of the year. Eleven people died and 27 others are missing after torrential rains battered southwest China's Chongqing, a municipality in the upper reaches of the Three Gorges Dam, causing thousands of houses to collapse, state media said. (Photo by AFP Photo/Stringer)

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)

A visitor and an employee dressed as Snegurochka (Snow Maiden), the granddaughter of Ded Moroz (Russian equivalent of Santa Claus), pose for a picture inside an upside down house, constructed as an attraction for local residents and tourists and located at the Royev Ruchey Park of Flora and Fauna in the suburbs of Krasnoyarsk, Russia, December 7, 2016. (Photo by Ilya Naymushin/Reuters)

President Barack Obama with does the tango with a dancer during the State Dinner at the Centro Cultural Kirchner, Wednesday, March 23, 2016, in Buenos Aires, Argentina. (Photo by Pablo Martinez Monsivais/AP Photo)

(L-R) Models Kylie Jenner and Kendall Jenner pose during the Universal, NBC, Focus Features, E! Entertainment Golden Globes After Party Sponsored by Chrysler held at the Beverly Hilton Hotel on January 8, 2017. (Photo by Christopher Polk/NBC/NBCU Photo Bank via Getty Images)

Medieval jousters Luke Binks (L) and Andrew McKinnon pose for a photograph in Sydney, Australia, August 16, 2017 during a photo call for the World Jousting Championships to take place in Sydney on September 23 and 24. (Photo by Dan Himbrechts/Reuters/AAP)