They say that on 9/11, the world changed. It certainly did change much about our world, and has reshaped the relationship (or lack of) between the west and the Muslim world. It continues to impact our daily lives – just ask anyone who has travelled by air, or look at the way the collective memory of American citizens leads them to react to events like earthquakes or large-scale accidents. New Yorkers seem to be living on a knife edge waiting for the next terrorist attack – as if their lives weren’t stressed enough already.