Documentary follows Syrian family's escape from ISIS

A Syrian family's desperate struggle to escape ISIS control has been documented in a secretly shot film by National Geographic.

The documentary by award winning filmmaker Sebastian Junger follows Marwan and his family as they covertly attempt to smuggle themselves out of Syria to escape the bloody atrocities of their extremist dictators.

Marwan, who has a son and two daughters, was horrified when his wife told him the Syrian city of Manbij - where his bother lives - had fallen to terrorist control.

His wife told him she saw boys' heads strung up in the city and a man in a cage howling because "nobody is put in the cage except for dogs".

"All the Syrians will have their turns. We'll all be put in the cages and we will howl," Marwan solemnly replied.

The father-of-three said beheadings are the horror tactic used to silence people and keep them under the thumb of their ruthless ISIS leaders.

"They gather everyone and force them to watch it. If you protested you'd be hung up for three or four days," he said.

"For me Christian, Armenian, Jewish, no problem. They do their thing and I do mine. This is our religion. You can't just call someone and infidel and behead them. I teach my children than our religion is one of forgiveness."

As winter approaches, the young family start to lose hope with their repeated attempts to pay a smuggler for access out Syria failing. Eventually, Marwan makes the risky decision to try and escape without a guide.

Lying in the back of a truck, the young family are filmed approaching the border knowing full well they will be publically executed if discovered.

"When we arrived at the border I was terrified. My wife started shaking. I prayed," he recalled.

But by sheer luck alone, ISIS fighters didn't inspect the vehicle allowing the family to finally escape.