Ian Bremmer's Quick Take:

Hi everybody. It's the 20th anniversary of 9/11 coming up real soon, and I thought I'd give you a few thoughts about it. I was here in New York, like so many of us, when the planes flew into the towers. It was shocking. I was in our offices in Midtown at the time. At first, of course, everyone thought it was an accident. And then suddenly it became quite apparent it was not. And it was a gut punch. It was a feeling that the world had changed inextricably even if you didn't know exactly how.