Revellers celebrate the New Year in Princes Street during Hogmanay street party celebrations in Edinburgh, Scotland January 1, 2015. (Photo by Russell Cheyne/Reuters)

Soniya, 6, whose family moved to Islamabad from Pakistan's Khyber-Pakhtunkhwa province to look for work, stands outside their house on the outskirts of Islamabad January 1, 2015. (Photo by Zohra Bensemra/Reuters)

Cara Delevingne and Kate Moss attend the Burberry Prorsum show during London Fashion Week Spring Summer 2015 on September 15, 2014 in London, England. (Photo by Anthony Harvey/Getty Images)

Mariachi musicians prepare to perform to celebrate the Day of the Virgin of Guadalupe outside the Basilica of Guadalupe in San Salvador, El Salvador December 11, 2015. (Photo by Jose Cabezas/Reuters)

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)

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)