This year marks the 20th anniversary of the 9/11 attacks in New York. The remembrance ceremony is broadcast live every year on the major TV networks.

Each year I plan to follow the live telecast in its entirety, but I can only bring myself to watch a few minutes of the ceremony before I switch the TV off – the telecast simply evokes and amplifies too many painful memories. In feeling this way, I can only assume I am not unlike many others who were here in New York on that sad and tragic day.

I can still clearly recall the roar of the engines of the 767 as it flew low and fast overhead heading towards the southern tip of Manhattan. I remember the sense of unease and confusion when the early morning television news reported the first crash. The news reporter got it wrong initially – they speculated that a light aircraft had accidentally hit the North tower.

When it became clear after the second crash that something horrible beyond imagination had happened, I remember feeling sick in the pit of my stomach.

Some of us react to emotional trauma by clinging to our daily routines, and I remember heading unthinkingly to my office at the UN on that clear September morning. And I recall the sombre mood of everyone in that subway carriage on the B train to the Bryant Park subway stop – we were all visibly shaken and distraught.

When I exited the stop at Bryant Park, I remember joining the crowd of people milling around and staring anxiously down 6th Avenue at the huge dark plumes of smoke billowing into the crystal clear sky. I remember the scene was too much for me to bear and I had to quickly avert my eyes.

I remember the courage and bravery of those first responders. And I remember the grief stricken desperately searching for their loved ones with a flood of flyers that appeared virtually overnight around the city

I remember the transformation of Union Square as New Yorkers converged there in droves to grieve. I remember how our planned visit ended abruptly because we turned home a block away from Union Square when we were overwhelmed by the raw emotion of the moment.

And I remember we all asked “Why?”