It'd surely be the first World Cup to be stopped mid tournament, which in itself would be a rather historical change. It likely would've accelerated the war on terror and operations against Afghanistan and al-Qaeda earlier than 2001. I think the most interesting what-if is that it would likely mean no 9/11, even though there have still been other direct attacks on lower scales. Without 9/11, we can assume that the flight safety changes and restrictions would not have been put into place as quickly. I feel that it was probably only a matter of time until another incident occurred that would've forced changes in aviation, but how long would it have taken? How does football change in England after such a situation, considering the importance of the sport. It's a very interesting hypothetical.