Barriers stand as police officers inspect the scene where a truck drove into a Christmas market in Berlin, Germany, on Tuesday, Dec. 20. 2016. Chancellor Angela Merkel said that German authorities were working on the assumption that the deaths of 12 people after a truck plowed into a Christmas market were a terrorist attack, and pledged to use the full force of German law to bring the perpetrators to justice. Photographer: Jasper Juinen/Bloomberg via Getty Images