The US launched its war in Afghanistan just weeks after the 9-11 attacks to find Al Qaeda leader Osama Bin Laden, and defeat the Taliban fighters who supported him. But nine years on Bin Laden remains at large. And al-Qaeda and the Taliban have joined forces against the U.S. and its allies, their ranks swelled by an influx of foreign fighters. Al Jazeera has gained exclusive access inside a Taliban group in northern Afghanistan, Sue Turton has our report.