I remember being in high school in Pittsburgh, 2nd period Business class, when we heard. I had a cell phone at that, but couldn't get ahold of anyone (Dad was at work, mom was actually here at OSU). Had to wait for the bus and watch everything unfold on the little TV we had in our homeroom. I never wanted to be home more in my entire life, especially after the last plane went down in Shanksville.
I'm also reminded of it a lot as my father-in-law is a retired police officer as well as a police chaplain for 22 years, and was a first responder who got to Manhattan two days after the attack. I've met several of the people who were there and that he's worked with over the past several years and even though many of them are sick now or have passed because of illness tied to recovery work (my father-in-law is still healthy thankfully), they all said they would do the same thing again if it happened tomorrow. Even though shit sucks right now in this country, it's still good to know there are still decent people out there willing to risk their own lives.