As Europe prepares to celebrate Christmas - it's also stepping up security measures. The German Chancellor has ordered a security review following Monday's attack on a Christmas market, in which 12 people were killed, and dozens injured.br br RT LIVE br Subscribe to RT! br Like us on Facebook Follow us on Twitter Follow us on Instagram Follow us on Google+ Listen to us on Soundcloud: br RT (Russia Today) is a global news network broadcasting from Moscow and Washington studios. RT is the first news channel to break the 1 billion YouTube views benchmark.