A Palestinian protester, dressed as Santa Claus, reacts after inhaling tear gas fired by Israeli troops during clashes in the West Bank city of Bethlehem December 23, 2016. (Photo by Mussa Qawasma/Reuters)

Students of the General Yermolov Cadet School wait to board an airplane for a parachute jump at an airdrome in the village of Novomaryevskaya outside the southern city of Stavropol, Russia, May 13, 2016. (Photo by Eduard Korniyenko/Reuters)

An army tank fires during a firefight against militants linked to al Qaeda near the southern Yemeni city of Zinjibar May 30, 2012. (Photo by Reuters/Yemen's Defence Ministry)

A security guard looks at the models during La Perla’s presentation at the Dream Hotel. Mercedes-Benz Fashion Week, New York City, Spring 2014. From the series “Fashion Lust”. (Photo by Dina Litovsky)

A pigeon rests on a wild iguana in a tree inside Seminario Park in Guayaquil, Ecuador, Thursday, April 3, 2014. Pigeons coexist with the wild iguanas at this park in the middle of the city surrounded by savannah. (Photo by Dolores Ochoa/AP Photo)

A tribal Fulani man milks a cow at a local milk collecting centre in Dangwala Karfi village on the outskirts of Nigeria's northern city of Kano January 19, 2016. (Photo by Akintunde Akinleye/Reuters)

Seals dressed in military uniforms swim during a show marking the 70th anniversary of the end of World War Two, at an aquatic park in the Siberian city of Irkutsk, Russia, May 9, 2015. (Photo by Evgeny Kozyrev/Reuters)

People carry the body of a man they uncovered from under the rubble of houses destroyed by Saudi airstrikes in the old city of Sanaa, Yemen, Friday, June 12, 2015. (AP Photo/Hani Mohammed)