A woman takes part in a four-minute flash mob pillow fight at the Old Town Square in Prague, Czech Republic, December 22, 2016. (Photo by David W. Cerny/Reuters)

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)

Santi Diaz Mosquera, 41, a “percebeiro” (barnacle fisherman), collects barnacles on rocks on the coast of Ferrol, in the northwestern Spanish region of Galicia, December 15, 2016. (Photo by Nacho Doce/Reuters)

Members of Hashid Shaabi or Popular Mobilization Forces (PMF) fire towards Islamic State militant positions in west of Mosul, Iraq, December 28, 2016. (Photo by Reuters/Stringer)

An Israeli Air Force F-35 fighter jet flies during an aerial demonstration at a graduation ceremony for Israeli airforce pilots at the Hatzerim air base in southern Israel December 29, 2016. (Photo by Amir Cohen/Reuters)

Actors wrapped in blankets react at the set of the post-apocalyptic movie “Zombie Era” at an abandoned factory complex in Langfang, Hebei province, China December 16, 2016. (Photo by Damir Sagolj/Reuters)

English actress and model Elizabeth Hurley launches Harrods beach and children's wear at the Knightsbridge store in London, England on December 6, 2006. (Photo by Daniel Deme/WENN)

Two visitors take pictures of autumn leaves at Rikugien Garden Tuesday, December 10, 2019, in the Bunkyo district of Tokyo. (Photo by Jae C. Hong/AP Photo)