It was still early in the morning. Not all the lawyers and secretaries were in the office yet. I was at my desk, working away. Suddenly there was a huge bang and the building shook violently, swayed back and forth. I tried to stand but couldn't. Even the windowpanes seemed to bend.

Outside there was a storm of debris - papers, concrete, glass - falling. I thought immediately it was a terrorist attack and felt sure that the building was going to collapse. I ran out into the hallway to the stairwell. The stairs were filled with people, smoke, dust in the air. But it was strangely calm. Very little shouting or screaming.

We made a space to the right of the stairwell for the injured to get down and the firefighters to ascend. Soon the traffic on the stairs was jammed. Some people had cell phones and there was a faint rumor that a second plane had crashed into Number Two.

Everything came down to one simple fact - we wanted to get out. The smoke was dense and the floors were treacherous from streams of sprinkler water coming down the stairs. My shoes kept slipping from underneath me. It took well over an hour, maybe 90 minutes, to get near the bottom.

And then - when we were on the seventh floor - there was a huge crash and we were sure then that there had been another bomb - we found out later that the neighboring Tower Two had fallen.

Everything went pitch black. No electricity. A tunnel of black. That's when I thought it was certainly all over. I was thinking of RoseMarie (wife), of all you guys (two sons, one daughter), and the kids of course, the grandkids.

The firemen were showing us the way. Without them we were lost. The rest is a haze. We got to the mezzanine. A woman fell. She said she could go no further. We dragged her for a few yards, through six inches of water, and then some of her co-workers helped her.

When I stepped outside to the plaza it was unreal. Debris, girders, masonry. The air was thick with a blinding white dust-light. It was like stepping into a morning snowstorm.

I began walking through the remnants of streets. Church Street. Trinity. Everything was utterly changed, destroyed.

Apart from the physical experience - the firemen shouting, the sound of sirens, the feel of my shoes slipping in the water - it might have difficult to know whether I was alive or not.

Yet the one thing I will never forget, it still brings tears to my eyes, it always will, it was the faces of the firemen as they climbed the stairs to help us. Young men, so young.

They were going up the stairs as we went down. It rips me up to think of them. They came to rescue us. And they were ones left behind. That will forever remain with me.