Each person remembers clearly what he or she was doing on the day that critical events took place. I was teaching when 9/11 occurred. The first thing I did was phone my wife (who is an American living in Canada) and tell her to turn on the TV.
She started to ask me why. I didn't know what to say. It was about 9 o'clock (am) our time. I told her just to do it. I wasn't sure what exactly was going on, but there were a lot of students crowded around the TV. It struck me that it must be important. I normally teach Math, but on that day nothing was taught. As the attack sunk in, we silently kept vigil that day, mourning the fact that man finds it necessary to murder innocents.
I was also teaching when Kennedy was shot. I had exactly the same reaction -- a sadness that was hard to live through. We never learn.