Was it the day that changed the world?
Some polling from YouGov earlier in the week found that 91% said they can remember what they were doing when news of the 9/11 attacks broke.
This compares with 84% remembering where they were when Princess Diana died, 68% when the 7/7 attacks on the London tube took place, and just 25% when Margaret Thatcher resigned as Prime Minister.
That puts it into context.
In many ways it was the day that changed the world and we see the consequences of that every day.
My big political memory is of the daily press conferences by then New York mayor, Rudy Giuliani, which were a model of how political leaders should respond to a crisis and bring a level of reassurance to the city and a broader audience.
All he was doing was listing statistics and making announcements of what was happening but his whole manner was just right for the days and weeks that followed.
We look to political leaders to appear to be in control and that’s what Giuliani achieved.