The U.S.-led coalition in Afghanistan has ended its combat mission, marking the formal end to the longest war in American history. American warplanes began bombing the country on Oct. 7, 2001, less than a month after the 9/11 attacks. Their goal was to drive the ruling Taliban from power. A total of 3,485 allied troops died in Afghanistan over the past 13 years, including 2,356 Americans. The war cost U.S. taxpayers, past, present and future, about $1 trillion.