I consider it a valid concept, and taken as a reference point in my life, where was I when I heard John Kennedy was shot? Vaguely remember being at school, but Bobby Kennedy was different and I remember always the exact second there was a news flash on Radio 1 show that morning. We were on school hols and we listened to the news for the next few hours whilst he was being operated on.
Pete Duel for me is another one, I was in my room listening to records and my brother shouted up to me, it was New Years Day morning.
In my mind's eye I can recall the colour of the wallpaper on the stairs at home, the type of TV we had, all the little details of the house, which on days like that and in moments like that, must burn onto your brain with the whole impact of the news, but if anyone were to ask me what colour wallpaper we had on the stairs in January 1972, I would have no clue, it is information that only comes to mind when I recall that one memory.
I can also vividly see the hospital bed with curtains around from 18 months ago when my dad died suddenly, I know what colour they were when i picture that image. I have been to hospital many times, but I couldn't tell you the colours of any of the curtains I saw on any other occasion with such certainty.