I'm currently in the USA where, unsurprisingly, there is a lot of TV coverage of the events of that terrible day.
We were at home (in normal retirement mode) when a friend telephoned to tell ys to watch BBC news. The OH and I sat in the study watching events unfold in almost complete silence for several hours. I did put a tape in the video recorder and switch it on, but that tape has never been touched since the moment I removed it after it rewound itself at the end.
There are no words for the enormity of the events of that day, nor any way of forgetting what happened. RIP to the thousands who died.