In December 2001, the U.S. military defeated the Taliban in Afghanistan. Democracy flourished and women came back to the workplace. But the U.S. invasion of Iraq changed everything. With Washington now focused on Baghdad, the Taliban saw an opportunity to take back control of Afghanistan. Violence intensified, and American military casualties grew. Richard Engel reports on America's long history in the country and on early efforts to hunt down Osama Bin Laden in the weeks after 9/11.