In the wake of the Berlin truck attack, police departments around the U.S. are making a show of force at places where crowds gather at Christmastime. In New York City, police dispatched heavily-armed counterterrorism officers to stand guard at crowded pop-up Christmas markets in Union Square, Bryant Park and Columbus Circle only an hour after news broke Tuesday about the carnage in Berlin, where a stolen truck slammed into a crowd and killed 12 people.