WATCH: Film tells story of US ‘horse soldiers’ on mission after 9/11

Doug Stanton, executive producer of “12 Strong: The Declassified True Story of the Horse Soldiers,” released Friday, explains how CIA paramilitary officers and US Army Green Berets, responding to President George W. Bush’s call, traveled by horse in Afghanistan, immediately after the September 11 attacks, and achieved incredible success in seizing Taliban strongholds.