but that is precisely what this man did. >> during the months i was preparing the trip every night i felt a knife on my throat. i felt it physically. >> jurgen is a german journalist. last year he crossed the border into isis territory. >> i think you must know your enemy if you want to defeat him. >> he went to mosul, an iraqi city about the size of philadelphia. population around 1.5 million. it's the biggest prize isis has captured. this extraordinary video gives us a rare look into everyday life under isis. it brings to mind the writer