Ali Hussein Kadhim, an Iraqi soldier and a Shia Muslim, was captured in the city of Tikrit by so-called Islamic State militants in June 2014.
He says he will never forget what happened next to him and an estimated 1,700 military cadets.
The cadets, many of them young teenagers starting their careers in the military, were lined up in groups and shot.
This is Kadhim’s own account of how he “miraculously” escaped the massacre at Camp Speicher.
UK viewers can watch ‘Once Upon a Time in Iraq: Episode 5’ on Monday 10 August at 21:00 BST on BBC Two and on BBC iPlayer.
Digital Producer: Ahmen Khawaja
Commissioning Editor: Kimberley Rowell
Please subscribe HERE