Our journey into jihad: the father and son who braved the dark heart of Isis

There is a roundabout in the centre of the Syrian city of Raqqa where few dare to tread. The swirl of decorative concrete surrounded by a wrought iron fence was once intended as a cheery municipal feature. But nowadays it is one of the most dangerous places on earth; where the world’s most brutal terrorist group displays the severed heads of its enemies.