A tribesman loyal to the Houthi movement carries his rifle as he leaves a gathering held to show support for the group, in Yemen's capital Sanaa December 15, 2015. (Photo by Khaled Abdullah/Reuters)

Veterans of the Bangladesh war of liberation march past during the celebration of the country’s 45th Victory Day at the national parade ground in Dhaka December 16, 2015. (Photo by Ashikur Rahman/Reuters)

Tourists watch the sunrise and pray outside a church on the summit of Mount Moses, near the city of Saint Catherine, in the Sinai Peninsula, south of Egypt, December 9, 2015. (Photo by Amr Abdallah Dalsh/Reuters)

Refugees disembark and make their way to a camp at a hotel touted as the world's most northerly ski resort in Riksgransen, Sweden, December 15, 2015. (Photo by Ints Kalnins/Reuters)

Contestants for the Miss World grand final perform in colourful costumes during a dress rehearsal in Sanya, Hainan province, China, 18 December 2015. (Photo by How Hwee Young/EPA)

Tourists play in the Harbin Ice And Snow World during its test run on December 22, 2015 in Harbin, Heilongjiang Province of China. (Photo by ChinaFotoPress/ChinaFotoPress via Getty Images)

People hold out money as butchers sell their remaining produce of the year at discounted prices during the traditional Christmas Eve auction at Smithfield's market in London December 24, 2015. (Photo by Neil Hall/Reuters)

A couple watches the sunset over a sea of fog covering the Geneva Lake from Chardonne, Switzerland, 28 December 2015. (Photo by Jean-Christophe Bott/EPA)