Cologne will flood the city center with 1,500 police officers on New Year's Eve, 10 times more than in 2015, to prevent a repeat of the sexual assaults and robberies committed mainly by young North African and Arab migrants last year. The police chief of Cologne on Thursday promised New Year’s Eve revellers that they can party safely this year after the city made global headlines in 2015 with hundreds of sexual assaults and robberies committed predominantly by young men of North African and Arab origin around the train station and cathedral.