ISIS,'the Islamic State of Iraq and the Levant', stunned the world last month by capturing Mosul, Iraq's second city. For Our World, Yalda Hakim has returned to Northern Iraq, a region she reported from last year, to find 4 people she met on her last visit - all members of a local paragliding club. She discovers how the arrival of ISIS has changed their country - and their lives, and asks if the ISIS declaration of an Islamic State, or Caliphate, marks the beginning of the end of Iraq as a country.