Children pat an elephant at the mobile Diva circus in the town of Molodechno, some 70 kilometers northwest of Minsk on September 3, 2015. (Photo by Sergei Gapon/AFP Photo)

A Pakistani monkey handler Naseer Khan plays flute to attract passers by for a monkey show to earn his living in Islamabad, Pakistan, Monday, September 7, 2015. (Photo by B. K. Bangash/AP Photo)

An aerial view shows the Amazon rainforest at the Bom Futuro National Forest near Rio Pardo in Porto Velho, Rondonia State, Brazil, September 3, 2015. The town of Rio Pardo, a settlement of about 4,000 people in the Amazon rainforest, rises where only jungle stood less than a quarter of a century ago. Loggers first cleared the forest followed by ranchers and farmers, then small merchants and prospectors. Brazil's government has stated a goal of eliminating illegal deforestation, but enforcing the law in remote corners like Rio Pardo is far from easy. (Photo by Nacho Doce/Reuters)

A flight deck crew prepares to launch a F18 Super Hornet from the deck of the USS Eisenhower off the coast of Virginia, December 10, 2015 in the Atlantic Ocean. US Defense Secretary Ash Carter visited the carrier with India's Minister of Defense Manohar Parrikar to demonstrate US Navy aircraft carrier flight operations. (Photo by Mark Wilson/Getty Images)

Actress Frederique Bel attends the Opening ceremony and the “Grace of Monaco” Premiere during the 67th Annual Cannes Film Festival on May 14, 2014 in Cannes, France. (Photo by Pascal Le Segretain/Getty Images)

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 Siberian tiger at a photographer for getting too much in its face during the presentation of two new Siberian tigers at Cabarceno Natural Reserve in Cabarceno, northern Spain, 21 July 2014. (Photo by Pedro Puente Hoyos/EPA)

Spencer Slate, costumed as a scuba-diving Easter bunny, is shown in this handout photo provided by the Florida Keys News Bureau as he hides eggs amid eel grass, in the Florida Keys National Marine Sanctuary off Key Largo, Florida March 31, 2013. About 80 adults and children participated in an Underwater Easter Egg Hunt, seeking real hard-boiled eggs painted with non-toxic food coloring to avoid adverse effects on the marine ecosystem. (Photo by Bob Care/Reuters/Florida Keys News Bureau)