A homeless man rests on the side of a street at the old quarter of Yemen's capital Sanaa November 27, 2015. (Photo by Khaled Abdullah/Reuters)

A Taiwanese woman takes a photo of a Christmas tree decoration at a street in Taipei, Taiwan,13 December 2015. (Photo by Ritchie B. Tongo/EPA)

A man rides his loaded tricycle next to three schoolgirls in Shanghai on December 11, 2015. (Photo by Johannes Eisele/AFP Photo)

Actors perform the living Nativity biblical scenes in Postojna cave in Postojna, Slovenia, December 22, 2015. (Photo by Srdjan Zivulovic/Reuters)

In this Tuesday, December 15, 2015 photo, an Afghan man sells traditional sauces and pickles on a street in Kabul, Afghanistan. (Photo by Massoud Hossaini/AP Photo)

An incredible clear-air lightning display from storms to the east of Noonamah, just outside Darwin on April 6, 2015. (Photo by Jacci Ingham/The Guardian)

Model Yasmine Petty arrives on the Life Ball plane on May 15, 2015 in Vienna, Austria. The Life Ball, an annual charity ball raising funds for HIV & AIDS projects, will take place on May 16, 2015 at the city hall in Vienna. (Photo by Monika Fellner/Getty Images)

A picture made available on 08 July 2015 showsa lightning strikes during a heavy storm over Poznan in the night of 07 July 2015. Severe storms passed last night over Poland causing lots of damages to buildings, trees, electricity and railway tractions. (Photo by Lukasz Ogrodowczyk/EPA)