The Rise of ISIS

FRONTLINE: From veteran producer and journalist Martin Smith, this documentary is a major, in-depth investigation of the terrorist group's ascent. Smith draws on interviews with Iraqi politicians and American policymakers and military leaders to explain how ISIS developed into what one interviewee calls 'the al-Qaeda that Osama bin Laden only dreamed of building'. The programme traces how ISIS gained strength in Syria, how it is funded, how it operates and how it draws recruits from up to 80 countries.