At the start of the Iraq War in 2003, over 600 journalists and photographers are given permission by the US government to follow the conflict as embedded reporters.
Photographer Ashley Gilbertson is working for The New York Times when he enters the city of Fallujah with a US marine battalion.
Fallujah, 40 miles outside Baghdad, would be the deadliest battle the marines would fight since the Vietnam War.
Just over a week after entering the city, a small group of them is ordered to escort Ashley on a recce of a local minaret – what happens next will change their lives forever.
UK viewers can watch ‘Once Upon a Time in Iraq: Episode 3’ on Monday 27 July at 21:00 BST on BBC Two and on BBC iPlayer.