Giant panda Meng Meng plays on a tree at a Siberian tiger-breeding base in Changchun, China on December 10, 2015. (Photo by Xu Chang/Xinhua Press/Corbis)

Karis, an eleven week old lion cub, plays in fallen leaves brushed up by keepers in her enclosure at Blair Drummond Safari Park, near Stirling, Scotland, on November 20, 2013. (Photo by Andrew Milligan/PA Wire)

Couples take part in the “Love and Challenge Marathon” in Hanoi, Vietnam, 16 August 2015. Fifty couples, who are going to get married, participated in the event which is held the fifth time. This year, the winners of the marathon received a honeymoon trip to Malaysia. (Photo by Luong Thai Linh/EPA)

Indonesian rescuers search for victims of the crashed military airplane in Medan, North Sumatra, Indonesia, 30 June 2015. At least people 49 people were killed after an Indonesian military plane crashed in North Sumatra and burst into flames, officials said. Air Force chief Air Marshal Agus Supriatna said there were no survivors after the plane ploughed into houses and commercial buildings in Medan, the country's third largest city. The plane left Jakarta with 113 people aboard, including military personnel and their relatives, but it was not clear how many continued the journey to Medan after stopovers in Pekanbaru and Dumai, Agus said. (Photo by Dedi Sahputra/EPA)

Germany's Angelique Kerber reacts after popping a bottle of champagne, a day following her win in the final match at the Australian Open tennis tournament, at the Government House in Melbourne, Australia, January 31, 2016. (Photo by Issei Kato/Reuters)

Fish weighing over 80 kilogram is cooked in a hotpot during a food festival in Zhengzhou, Henan province, China, October 17, 2015. (Photo by Reuters/Stringer)

In this photo taken Sunday, October 5, 2014, a library official shows a 13th-century German prayer book containing the earliest evidence of the Yiddish language, at Israel's National Library in Jerusalem. This week, Israel's National Library gave The Associated Press a rare peek at a selection of rare historical manuscripts in its collection. (Photo by Sebastian Scheiner/AP Photo)

A Tibetan Buddhist nun spins a prayer wheel in sub zero temperatures at a Buddhist laymen lodge where thousands of people gather for daily chanting session during the Utmost Bliss Dharma Assembly, the last of the four Dharma assemblies at Larung Wuming Buddhist Institute in remote Sertar county, Garze Tibetan Autonomous Prefecture, Sichuan province, China November 1, 2015. (Photo by Damir Sagolj/Reuters)