Has it really been ten years? I remember it, clear as day.
The two German classes were in Mr Pollard's and Mr Chesire's rooms respectively, overlooking the old Quad. At about a third of the way through the lesson, Mr Pollard came to the door, ashen faced, telling us and Mr Chesire to come into his form room to watch the events unfold.
We were all around the age of 13 - I had turned 14 only two days before as one of the youngest in my year.
We sat, and watched the repeated footage of the first plane crashing into the North Tower. We would later be told it had been American Airlines Flight 11. Then the unthinkable happened. A second plane appeared - and disappeared - as it hit the South tower.
No one spoke for some time afterwards. With the replayed footage earlier, many of us had not really understood exactly what was happening.
Meanwhile, my father was working in his office at the Nat West offices in central London. He, and many other money market dealers, had been on the phone to people in both towers, and after the first plane had hit, the news channel had been switched onto the television which normally showed stock market shares. One dealer had called out for someone to "switch that bloody disaster movie off" before a round of angry responses silenced the dealer in question.
The whole Nat West office followed my father's lead - everyone on the phones was telling the dealers still there to get out of the buildings. They were literally screaming down the phones, "get out - go, get out, you're not safe", as the second plane hit. The man on the end of the phone to my father went silent. I was later told that he was one of the few to make it out alive of the South Tower.
The world seemed to turn on its head that day. When the bell went for break, everyone stayed in the old quad, talking quietly about the day's events.
We watched more of it later that afternoon, watching the towers collapse, the aftermath of several hours sustained fires in the building - and it was only when we saw the dust clouds rising over New York that it really hit home the seriousness of the whole damn thing.
The images in newspapers, magazines, on television and online later that day, week, month, year - were
incredible in their subject, but at best devastating. The brave men and
women of the New York fire and police services had lost a great many
people who tried to save as many as they could. The damage, both in terms of the destruction, and the loss of life were there for all to see.
Two giant towers - 110 floors high - which had dominated the skyline in New York for nearly thirty years. All of us - bar the teachers - had grown up in a world where these buildings existed. The death toll was insurmountable, and fluctuated wildly in the weeks that followed.
66 British Citizens would perish in the attacks. 372 foreign nationals of around 56 nationalities also died. 2669 American citizens died.
The site of the world trade centre has a memorial garden, which is still at this point, under construction. The design has been described as "reflecting absence".
Reflecting Absence. A perfect dedication for the event which changed the world forever.