(CNN) -- Best-selling author and director Sebastian Junger says experiencing the existence of U.S. troops' experience in Afghanistan was like being "on Mars."
Junger documented the reality of an Army platoon as its soldiers lived, fought and died at one of the most dangerous postings in the U.S. military, a 15-man outpost called Restrepo in Afghanistan's Korengal Valley. It's the focus of Junger's new feature-length documentary, also named "Restrepo."
The outpost, Junger told CNN's Campbell Brown in an interview Thursday night, was hellish. "The first time I was up there we were attacked four times in one day. No running water, they didn't bathe for a month at a time. No internet, no phone, no electricity at first," he said.
Junger said that after a few weeks at their base in Italy, the platoon's members just wanted to get back to Restrepo. "What was going on up there was brotherhood, very different from friendship. Brotherhood, you don't even have to like the guy, but if he's your brother, you'll protect him, you'll die for him. They all felt that way."
While "Restrepo" is not a political film, Junger does believe NATO troops are making progress in Afghanistan, with violence in the country at a 30-year-low.
"Sixteen thousand Afghan civilians have died because of NATO combat operations in Afghanistan since 2001 -- a horrifying number, but it pales comparison to the civilian deaths in the '90s. Four hundred thousand Afghan civilians died in the '90s... The question is, does the world have the staying power to see it through."