A new wave of films documenting the war in Afghanistan is proving more realistic than ever - with the latest following an injured marine having difficulties adjusting to life at home.
In July 2009, hundreds of US marines from the 8th Regiment's 2nd Battalion landed deep behind hostile lines in southern Afghanistan at the start of a major assault against the Taliban. Within hours they were surrounded and attacked from all sides.
In the fighting that followed, one marine was killed and several others collapsed from heat exhaustion.
Amid the chaos of battle, a photojournalist embedded with Echo Company, Danfung Dennis, was handed a precious bottle of water by a 25-year-old sergeant, Nathan Harris.
It was the start of a friendship that would change both their lives.
"Sgt Harris was an exceptional leader," says Dennis.
"He had done two deployments already to Iraq and Afghanistan and he was the first marine to step off the helicopter during the assault.
"We slept in the same dust, ate the same instant meals and learned to trust one another."
A changed man
When the marines returned to their base at Camp Lejeune, North Carolina, at the end of their seven-month tour, Harris was missing.
The squad leader had been seriously injured in a Taliban ambush two weeks earlier.
Danfung Dennis tracked him down to his home in the small town of Yadkinville, more than 250 miles (402km) west of the base.
The person he found there shocked him.
"He was a shell of the man he was in Afghanistan," recalls Dennis.
"He had been shot in the hip and had nearly bled to death and had undergone surgery five times.
"He was in extreme pain and distress and he was trying to reintegrate into a society that had no understanding of what he had just been through.
"He relied on his wife Ashley for everything - getting dressed in the morning, taking his medications, doing his physical therapy.
"He was struggling with trying to understand what it means to be a warrior when you can't fight any more."
Sgt Harris' struggle to make the transition from the battlefield to the home front is the subject of an award-winning documentary, Hell and Back Again.
It charts his increasing dependence on prescription painkillers, his attempts to rebuild his relationship with his wife and his mood swings, which lead at times to erratic and even menacing behaviour.
Hell and Back Again is the latest in a series of critically lauded documentaries to combine visceral footage from the Afghan front line with a deeper exploration of the lasting impact of war on its participants.
The personal dangers faced by the makers of all three films aren't merely hypothetical.
Restrepo's co-director, Tim Hetherington, was killed in April while on assignment in Libya. He had attended the Oscars ceremony in Los Angeles less than two months earlier.
"When we were making the film there were many moments when we could have been killed," Hetherington told me in an interview shortly before his death.
"When you used to leave the wire, the sense of mortality was heightened because it was very easy to get killed on an ambush.
"Life and death was a reality and there were moments that were very traumatic."
Iconic images
War has fascinated film-makers ever since the silent epic The Birth of a Nation (1915) and early talking movies like All Quiet on the Western Front (1930).
Film journalist Edward Lawrenson believes the long history of fictional war films has directly influenced today's documentary makers.
"It's impossible to see images of the war in Afghanistan with helicopters picking up the dust clouds without thinking of films like Apocalypse Now," Lawrenson says.
"These are just the icons of our age. I think the film makers are very conscious of the legacy of the war movies that preceded the conflict."
One of the main themes of Hell and Back Again is how veterans explain the extraordinary, life-changing experience of combat to their loved ones when they return home.
Major Jake Little was awarded the Military Cross for his leadership of a company of British soldiers from 2nd Battalion, The Yorkshire Regiment, during a fire fight in Helmand province.
He believes the recent wave of documentaries about Afghanistan give audiences a new insight into life on the front line.
"Prior to these films there was only a producer or a director's view of what warfare is like," says Major Little.
"These films are really giving you the reality in a way that I don't think we've seen before.
"For me, they clearly bring back memories - the sounds and the sights if not the smells come through."
Ten years after the start of US military operations in Afghanistan, the war is now the longest in the country's history.
Danfung Dennis believes a decade of conflict has desensitised many people to its horror.
By focusing on one US marine's journey to hell and back again, he says he hopes to shake viewers from their apathy towards complex events in distant lands - and show that for some veterans, their tour of duty does not end when they finally come home.
Hell and Back Again is released in the US on 5 October and the UK on 12 October.
