A hippopotamus performs during a show at the circus in Krasnoyarsk, Siberia, Russia, July 7, 2016. (Photo by Ilya Naymushin/Reuters)

Syrian girls carry bags with bread as people queue up outisde a bakery in a rebel held neighbourhood in the northern city of Aleppo on July 12, 2016. Since mid-2012, Aleppo has been roughly divided between government control in the west and rebel control in the east, and has suffered enormous destruction in the war that has killed more than 280,000 people nationwide. Last week, a government advance brought regime troops within firing range of the Castello Road, the only remaining supply route into the opposition-held east, effectively severing rebel neighbourhoods from the outside world. With their route to the outside world cut, there is no new flour coming to the city's bakeries, and fuel to light their ovens is also now hard to find. (Photo by Karam Al-Masri/AFP Photo)

A woman carries her child in a basket as she walks on a road in Allahabad, India, August 11, 2016. (Photo by Jitendra Prakash/Reuters)

A traffic police officer directs vehicles at a street junction during sunset in Pyongyang, North Korea, Thursday, August 25, 2016. (Photo by Dita Alangkara/AP Photo)

A tourist poses on the glass-bottom bridge at Zhangjiajie Grand Canyon on August 20, 2016 in Zhangjiajie, Hunan Province of China. The Zhangjiajie Grand Canyon's glass-bottomed bridge welcame its trial operation on Saturday and about 8,000 tourists crowded to view the grand glass bridge. (Photo by VCG/VCG via Getty Images)

Baby giraffe of Niger (Giraffa Camelopardalis) “Kenai” (R), born on August 25, 2016, kisses his mother “Dioni” on August 31, 2016 at the zoo of La Fleche, northwestern France. (Photo by Jean-Francois Monier/AFP Photo)

Rick Sorenson, owner of the Rio Ramaza Marina, wades in the Sacramento River after securing an old paddlewheel boat on his property as the river makes its way up the levee on Garden Highway in Sacramento, Calif., Monday, January 9, 2017. (Photo by Hector Amezcua/The Sacramento Bee via AP Photo)

Children hold signs thanking truck drivers hauling rocks to the Lake Oroville Dam after an evacuation was ordered for communities downstream from the dam in Oroville, California, U.S. February 13, 2017. (Photo by Jim Urquhart/Reuters)