The mood was heavy at Breitscheidplatz Christmas market as it reopened for visitors on Thursday.Just three days after a truck ploughed into visitors, killing 12 and leaving around 50 injured, stall owners unshuttered their wooden huts, many still in shock over the tragedy.The Christmas market that was attacked on Monday has already reopened. Berlin remarkably unaffected by the atrocity pic.twitter.com/b7WZCIGU0H— Bojan Pancevski (@bopanc) December 22, 2016Concrete barriers now surround the area and similar security measures were rolled at other Christmas markets across Germany. Critics of the German authorities pointed out that they should have already been installed after the CIA warned that Christmas markets were top terror targets.Berlin police install terrorist-proof concrete barriers around Christmas market as it reopens today https://t.co/D7VHRtQnNT pic.twitter.com/OGGKRRTyqa— Daily Mail Online (@MailOnline) December 22, 2016Some of the visitors were fighting back tears as they headed towards the makeshift memorial.Laying flowers at a makeshift memorial to victims of the Berlin Christmas market attack as market reopens. #breitscheidplatz #hbglobal pic.twitter.com/bWu7wvcpWC— Kevin O’Brien (@kevin11obrien) December 22, 2016Growing by the minute, a makeshift memorial of candles and flowers paid tribute to the victims. One message amongst the floral display meant for the perpetrator read ‘you will not divide us’.