BERLIN, GERMANY - DECEMBER 21: Police patrol a Christmas market the day it reopened following an apparent terror attack on another Christmas market in the city center on December 21, 2016 in Berlin, Germany. All of Berlin's approximately 60 Christmas markets had remained closed yesterday in a signal of respect and mourning for the victims of the Monday attack in which a man drove a heavy truck into the crowded Christmas market at Breitscheidplatz square, killing 12 people and injuring 48. (Photo by Michele Tantussi/Getty Images)
