raqqa. our international correspondent got rare access to the front lines for this exclusive report. reporter: we are now inside the city walls of raqqa, the capital of isis, in which they make their final substantial doubt in syria, and, really, the middle east. that wall, a key milestone for forces and the syria kurds and arabs who control 200 to 300 meters inside the city herement down that w200 meters, the forcs r and they don t move much in the daylight because of risk of snipers, or much in these streets, but night, the movement forward is, in fact, made. we saw u.s. forces here not far from the positions, not to be filmed or noticed, frankly, but it s them calling in air strikes and artillery allowing forces to move in quickly. i was surprised how little the