Saint Nicholas poses with students during a traditional parade in central Brussels, Belgium December 3, 2016. (Photo by Yves Herman/Reuters)

Pakistani civil society activists release lanterns into the sky in Lahore on December 15, 2016, as they pay tribute to victims on the second anniversary of an attack on The Army Public School in the city of Peshawar. Taliban militants attacked on Pakistani Army Public School in Peshawar, killing 151 people mostly children on December 16, 2014. (Photo by Arif Ali/AFP Photo)

Women wearing bikinis and Santa Claus hats participate in a promotional event to celebrate the upcoming Christmas at a ski resort in Xuchang, Henan province, December 23, 2014. Ten women wore Santa Claus-themed bikinis to welcome the coming Christmas in temperatures below zero Celsius. (Photo by Reuters/Stringer)

Inflatable dolls in the shape of ducks are seen in front of the National Congress during a protest against tax increases in Brasilia, Brazil, March 29, 2016. The campaign “I will not pay the Duck” is organized by the Federation of Industries of Sao Paulo (FIESP) and uses the duck symbol in reference to industries that pay high taxes. (Photo by Gregg Newton/Reuters)

A model presents a creation from the Jeremy Scott Spring/Summer 2015 collection during New York Fashion Week September 10, 2014. (Photo by Lucas Jackson/Reuters)

Couples kiss during a kissing contest in Wuhan, Hubei province, November 23, 2014. Some 20 couples attended the contest and the winners have been awarded an iPhone 6, according to local media. (Photo by Reuters/Stringer)

“The Net thrower”. The fisherman are conducting activities on Situgunung Lake. Photo location: Situgunung lake, Sukabumi, West Java, Indonesia. (Photo and caption by Dody Kusuma/National Geographic Photo Contest)

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)