20 years after 9/11, Hillary Clinton recalls ground zero looked "like the gates of hell"

Saturday marks 20 years since the September 11 terrorist attack that killed nearly 3,000 Americans and left many more with long-term health issues.

Just about a year earlier, Hillary Clinton had been sworn in as New York's junior senator. Clinton visited ground zero in Manhattan one day after the attacks, flying in with Senator Chuck Schumer. She described to "CBS Mornings" co-host Tony Dokoupil the level of catastrophic damage she saw. "We landed at LaGuardia, we took a helicopter, and we circled over ground zero. And I cannot imagine anything that looked more like the gates of hell. I thought I'd be prepared because I'd seen it on TV, but the TV screen contained it. And circling over it was something that I think about and will never forget," Clinton said.