In the ever-popular sick-fun AH pastime of making 9/11 even worse than it was (e.g. see
this recent thread), I like to raise the issue of a 9/11 expanded to "Old Europe", because the scenario of making Europe as PO and mad for revenge as the USA has interesting geopolitical and strategic implications: e.g. a NATO-wide effort would have easily made Afghanistan and Iraq turn quite different, or made the West leave Iraq alone, or go after Pakistan or Iran instead.
So, we assume that a more powerful, organized, and well-funded AQ picks more targets in the USA and one or more targets in each of Britain, France, Germany, Italy, and Spain, the latter five countries both because they are perceived as the main allies of America and for their alleged mistreatment of Muslims. At least an equal amount of targets for the USA and Europe, and for each European country. No attack fails (e.g. no Flight 93 successful rebellion), although the damage wrought of course depends on the structural features of the targets.
AQ picks targets that have high symbolic value and the potential to inflict serious economic and/or personal damage. According to the discussion in the other thread, for US targets I'd tentatively pick Twin Towers, the Pentagon, Empire State, Willis/Sears Tower, and the Capitol. This would mean at least one target each in Britain, France, Germany, Italy, and Spain. Which European targets do you suggest ?
Moreover, with an "Old Europe" that is howling for blood like America, and hence throws its military weight behind a NATO-wide major effort on War on Terror, which do you think would become the targets of the alliance ITTL:
A) Afghanistan alone
B) Afghanistan, then Iraq
C) Afghanistan, then Pakistan
D) Afghanistan, then Iran
E) Afghanistan, then Somalia
F) A combination of the above
EDIT: an optional further twist to the scenario is that Russia, too, is hit in addition to USA and EU (perhaps in retaliation for the war in Chechnya).