A pig's head is seen in a basin after it was slaughtered it in the village of Azerany, Belarus, December 12, 2015. (Photo by Vasily Fedosenko/Reuters)

Damaged buildings are pictured at night in Aleppo, Syria December 11, 2015. (Photo by Ammar Abdullah/Reuters)

Passengers travel on the London train and underground system during the Christmas party season, December 18, 2015. (Photo by Paul Hackett/Reuters)

People take photos with the skyline of the central business district in Singapore on September 10, 2015. (Photo by Edgar Su/Reuters)

A boy dressed as the Star Wars character Darth Vader attends a Star Wars themed church service, at the Zion Church in Berlin, Sunday, December 20, 2015. About 500 people, some carrying light saber props or wearing Darth Vader masks, attended the service, more than twice as many as usual on a Sunday. (Photo by Markus Schreiber/AP Photo)

A couple who did not give their names walk in downtown Havana, February 2, 2015. (Photo by Alexandre Meneghini/Reuters)

Emilio Gonzalez from Venezuela poses during the Cali Tattoo Festival in Cali, Colombia, September 12, 2015. (Photo by Jaime Saldarriaga/Reuters)

People are reflected in a shop window as they walk along a street in a shopping district in Tokyo, Japan June 25, 2015. (Photo by Thomas Peter/Reuters)