David and Samantha Cameron laid flowers at the World Trade Centre memorial on Thursday as they paid their respects to the victims of 9/11. The prim...

This week, we commemorate the loss of thousands of lives lost during and after the horrific terrorist attacks on the World Trade Centre ten years ago. It has been a sad decade, but it has ended with grounds for optimism.

Whenever I'm asked about my reaction to what happened on 9/11, as has happened quite a bit over the weeks leading up the 10th anniversary of the attacks, my mind flashes back to the moment when I first heard that the unthinkable had happened. I was at home in Los Angeles, getting my two daughters, then 10 and 12, ready for school, and thinking about a column I was planning to write that day. In an instant that all changed, of course. As we commemorate 9/11, we should also remember that this is also the 10th anniversary of 9/12, the day when the shock began to wear off, the full dimensions of the tragedy began to become clear, and the US began to decide what its reaction was going to be.