A low rumble shook the ground and a plume of dark grey smoke rose into the sky as I made my way to the Astoria subway station just before 8.45am on a brilliant autumn morning. I didn't realise it at the time, but the noise signalled the start of America's worst nightmare.
The enormity of what had just happened didn't hit me until I surfaced minutes later on 59th Street in Manhattan: I found myself plunged into a world turned upside down as crowds of people cried in bewilderment and fury at the outrage unfurling around them.
I was about a kilometre from the World Trade Centre, which was still standing after its hits by the two planes, but the smoke and noise of the disaster were everywhere. As I walked south on Lexington Avenue, people ran towards me shouting. They were in a state of shock, disbelief, and, most of all, anger.
One man in a dark business suit walked down Park Avenue towards the World Trade Centre buildings minutes before they collapsed, yelling over and over: 'Those sons of bitches.'
As the first of the towers collapsed, a collective scream rang out from the crowds. One woman sat crying on a bench. 'What next, what next,' she wept, rocking from side to side. A middle-aged man surveyed the scene and said to me: 'I think the whole world changed today.'
It was heart-wrenching to see the agony of the people here. I didn't know anyone who was hurt and this isn't my home, but the pain on people's faces was so powerful, I was swept up in the emotion.
