Taliban means "students" in Pashto, and at one point, leaders of the group were American allies. Here's how the Taliban conquered Afghanistan. RELATED: https://bit.ly/3z0pMJP WASHINGTON – Taliban fighters marched into Afghanistan's capital city on Sunday, signaling a collapse of the Afghan government two decades after the U.S. invaded the country in the "war on terrorism." The swift fall of the capital city came as the Taliban seized nearly all of Afghanistan, despite the billions of dollars spent by the U.S. and NATO to build up Afghan security forces. » Subscribe to USA TODAY: http://bit.ly/1xa3XAh » Watch more on this and other topics from USA TODAY: https://bit.ly/3B3N16t » USA TODAY delivers current local and national news, sports, entertainment, finance, technology, and more through award-winning journalism, photos, videos and VR.