A baby hippo swims under the water in its enclosure at Prague Zoo, Czech Republic, February 24, 2016. The baby was born on January 28, and is yet to be named. (Photo by David W. Cerny/Reuters)

A woman collects water from a stream outside the village of Tsemera in Ethiopia's northern Amhara region, February 13, 2016. (Photo by Katy Migiro/Reuters)

A child looks at a polar bear swimming under a water in its enclosure on a hot summer day at Prague Zoo, Czech Republic, July 30, 2015. (Photo by David W. Cerny/Reuters)

A baby dives as his mother holds on tightly during a water baby class in Odessa, Ukraine on August 6, 2016. (Photo by Andrey Nekrasov/Barcroft Images)

A helicopter is silhouetted by glowing embers as it makes a water drop at the “Old Fire”, which burned in Calabasas, California, U.S., June 4, 2016. (Photo by Gene Blevins/Reuters)

A girl pours water over a dog to cool it down, in the rebel held besieged town of Douma, eastern Damascus suburb of Ghouta, Syria, June 23, 2016. (Photo by Bassam Khabieh/Reuters)

A participant runs towards the waters of the North Sea during the annual New Year's plunge event in Ostend, Belgium, January 2, 2016. (Photo by Francois Lenoir/Reuters)

The heads of slaughtered water buffalos and a goat are lined up on the ground after the animals were sacrificed during “Dashain”, a Hindu religious festival in Kathmandu, Nepal October 10, 2016. (Photo by Navesh Chitrakar/Reuters)