The six-months-old female koala cub holds on to the back of zoo keeper Lena at the zoo in Duisburg, Germany, 23 October 2015. The yet unnamed baby weighs 580 grams. (Photo by Roland Weihrauch/EPA)

A visitor falls down as they run away from a wave caused by a tidal bore which surged past a barrier on the banks of Qiantang River, in Hangzhou, Zhejiang province, China, October 28, 2015. (Photo by Reuters/China Daily)

A boy performs a masked dance as he participates in a parade during the National Encounter of Mask festival in Barva de Heredia October 30, 2015. (Photo by Juan Carlos Ulate/Reuters)

A Palestinian woman paints a mural, depicting a masked Palestinian holding a knife, in support of Palestinians committing stabbing attacks against Israelis, in Rafah in the southern Gaza Strip November 3, 2015. (Photo by Ibraheem Abu Mustafa/Reuters)

A woman holds her umbrella while walking against strong winds as Typhoon Soudelor approaches Taiwan in Taipei, August 7, 2015. (Photo by Pichi Chuang/Reuters)

A girl reacts as she receives polio vaccine drops during a house-to-house vaccination campaign in Yemen's capital Sanaa, November 10, 2015. (Photo by Khaled Abdullah/Reuters)

An internally displaced girl stands on an abandoned railway tracks beside a makeshift refugee camp in Sinjar town, in Idlib province, Syria November 20, 2015. (Photo by Ammar Abdullah/Reuters)

A man smiles as he carries firewood he bought on a street amid ongoing fuel and cooking gas shortages in Yemen's capital Sanaa December 2, 2015. (Photo by Khaled Abdullah/Reuters)