A man and a girl take a dip in icy waters during celebrations for the Orthodox Epiphany in the Sea of Japan in the far eastern city of Vladivostok, Russia, January 19, 2016. Orthodox believers mark Epiphany on January 19 by immersing themselves in icy waters regardless of the weather. (Photo by Yuri Maltsev/Reuters)

A polar bear cub snuggles up against her mother Valeska, in their enclosure at Bremerhaven's (Bremen's) Zoo by the Sea, Germany March 9, 2016. The female cub, who is yet to ne named, was born on December 11 last year. (Photo by Carmen Jaspersen/Reuters)

A boy collects drinking water from a hand pump in Kutubdia, Bangladesh on March 30, 2016. Kutubdia is one of many islands affected by some of the fastest recorded sea-level rises in the world. The island has halved in size in 20 years. (Photo by SIipa/Rex Features/Shutterstock)

Female sea lion “Sarasa” holds a hose with her mouse to help a trainer clean her room at the Shinagawa Aqua Stadium aquarium in Tokyo on December 30, 2014. The aquarium is carrying out year-end general cleaning of their facilities. (Photo by Yoshikazu Tsuno/AFP Photo)

A woman works to create handmade Nepali Lokta paper in Kathmandu January 7, 2015. Lokta papers are made from the fibrous inner bark of Lokta bushes that are found over 5,000 metres above sea level. (Photo by Navesh Chitrakar/Reuters)

In this March 3, 2015 photo, a group of California sea lions rest on a large bouy in the San Ignacio lagoon, in the Pacific Ocean, near Guerrero Negro, in Mexico's Baja California peninsula. (Photo by Dario Lopez-Mills/AP Photo)

Partipants vie for the ball during the 11th Mud Olympics held at the North Sea coast in Brunsbuettel, Germany, July 11, 2015. Amateur athletes have competed in several disciplines at the Mud Olympics since 2004. (Photo by Axel Heimken/EPA)