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)

Girls dressed up in traditional Egyptian clothes from the early 20th century pose for a picture before they get their photos taken on the historical Al-Moez street of Islamic Cairo, Egypt, January 17, 2016. (Photo by Asmaa Waguih/Reuters)

German car manufacturer BMW presents the “Vision Next 100” concept car during the 100th anniversary celebrations in Munich, Germany, Monday, March 7, 2016. (Photo by Matthias Schrader/AP Photo)

In this January 7, 2016, photo, conservationists of Borneo Orangutan Survival Foundation hold a baby orangutan rescued along with its mother during a rescue and release operation for orangutans trapped in a swath of jungle in Sungai Mangkutub, Central Kalimantan, Indonesia. Last year's forest fires drove orangutans closer to the river bank, where they had to live in an over-populated swath of forest as thin as 30 meters wide along the river. (Photo by Dita Alangkara/AP Photo)

Hadeel, 10, asks a passerby for help to pay a medical bill as her father Shahrour, 54, sits in his wheelchair in the Douma neighbourhood of Damascus Syria February 3, 2016. Shahrour said he developed diabetes at the beginning of the war in Syria. A lack of insulin led to his medical condition worsening and his right foot had to be amputated. Recently he also suffered a stroke that paralysed half his face. He and part of his extended family, a total of 18 people, live together and struggle to get by. (Photo by Bassam Khabieh/Reuters)

These stunning pictures show a normally vicious tiger calmly swimming in a pool of algae, on Jule 9, 2014. The powerful cat takes a refreshing break by taking a dip in the bright green algae. But it looks like this big cat is scared of getting his head wet as he strains to keep it above the water. After splashing around for a bit the tiger gets out and tries to air-dry with specks of the vegetation dripping off his fur. The striking pictures were taken at Copenhagen zoo by snapper Soren Lundgren Neilson. (Photo by Soren Nielsen/Caters News)

“Sidney D. Gamble (July 12, 1890 – 1968) was born in Cincinnati, Ohio, to David Berry and Mary Huggins Gamble; grandson of James Gamble, who, with William Procter, founded Procter & Gamble in 1837. in 1912 he graduated magna cum laude from Princeton University with a Bachelor of Literature degree and was elected to Phi Beta Kappa. He visited China for four extended periods, 1908, 1917–1919, 1924–27, and 1931–1932, doing Christian social work for the Y.M.C.A and conducting social surveys. He is now best known for his remarkable and extensive photographs of Peking and North China.” – Wikipedia. (Photo by Sidney David Gamble via Duke University Libraries)

Photo: Hillcoat Riding Fu Tu. China, An Xian, 1917-1919. P.S. All photos are available in high resolution.