  The attacks alone would have been an event of the first order; but it was the belief-defying, heart-crushing fall of the towers that knocked history off its course.  (What would the world be like now if the girders holding up the buildings had managed to withstand the fires?  Would there have been a Camp X-ray in Guantanamo, a war in Iraq, a global "war on terror"?)
</p>
<p>
As it was, the towers' collapse added an element of the uncanny to the fantasy made real by bin Laden. Yet although the scale of the