U.S. troops pulled out of their main military base in Afghanistan on Friday, leaving behind a piece of the World Trade Center they buried 20 years ago in a country that could descend into civil war without them.
The quiet departure from Bagram Air Base brought an effective end to the longest war in U.S. history. It came as the Taliban insurgency ramps up its offensive throughout the country after peace talks sputtered.
The Pentagon said the turnover of Bagram to Afghan security forces was a "key milestone" in the withdrawal, but insisted the U.S. military still has the authority to protect Afghan forces.