>> something had clicked, where once he felt no sympathy for the victims of 9/11, the 7/7 attacks in london he says, made him feel revulsion. recently nawaz's journey almost took him from prison to parliament. he ran for a seat in this year's british elections. he's currently a chairman of a thinktank he co-founded to study extremism and challenge it. >> people that join isil, they genuinely think they're bringing about an end of days scenario. they genuinely believe they are working on behalf of god. nawaz's story sheds light on one crucial aspect of this picture. but what about the others? why are hundreds, thousands of people streaming from four corners of the world to fight for isis? why do young men -- and they are