I was based in a small district newsroom in Herne Bay, Kent, at the time, and we were busy working on our usual stories that afternoon when my colleague called our news editor and found her oddly distracted.
The journalists in our Canterbury office had spotted the first alerts go out on Teletext, which was always monitored for breaking news, and had turned over to watch the horror unfold on the television news.
In stunned and bewildered tones, they told us how the World Trade Center had been hit by first one plane - then another. I remember the shock in their voices when they called us back to tell us that two more planes had crashed, and that the Twin Towers had started to fall.
With no TV in our office, I didn't see the full scale of the destruction myself until I got home that evening and found my partner glued to Sky News, watching horrific images play round and round in a mesmerising loop while reporters filled the airwaves with everything they knew so far and endless speculation.
It was only later that I began to realise just how many people had died, including the many emergency workers who lost their lives desperately trying to save as many people as they could.
The final toll shows that nearly 3,000 people died as a result of the attacks on 9/11, and a further 6,000 were injured. I still can't really comprehend that scale of devastation.
Twenty years on, many of the fine details are a blur, but I remember the dead weight of impending war and real fear all around me about what was going to happen next - would similar terror attacks be perpetrated here? No-one knew.
A week after the attacks I was tasked with reporting on a service by the Archbishop of Canterbury at the city's Cathedral. Open to all comers, it was aimed at providing words of strength and comfort to the many shocked and scared people sitting around me. I clearly remember a woman weeping throughout the whole service, and wondering if she'd lost someone close to her, or whether the overall tragedy was simply too much for her to bear.
As a young reporter, just starting out in my own life and career, I was able to sit and observe the fear and sorrow of those around me with sympathy and curiosity, but I don't think I felt any of it as deeply as they did. Now, as I look back, I think the scale of what was happening was simply too big for me to comprehend at the time.
When we started talking about the 20th anniversary of these terrible events, everyone here started sharing their own stories, remembering where they were when they heard the news. The moment has seared itself as a date stamp in our minds.
So, I'm sure the answer is yes - you do remember where you were on that terrible day.