I watched this thing on 9/11 recently. The actual day it happened I was at a friend's house and we saw it on TV. But I didn't realise how bad it was at the time. But now, seeing the in-depth footage of people jumping to their deaths out of the twin towers really disturbed me. It is so unreal.
My research on sovereignty (see more by searching the 'sovereignty' label) really confirmed to me that not everything that happens is God's will, mainly because God's will as we read it in scripture simply does not reflect what we see in this world! And seeing something like 9/11 should make it so clear to us. I can't fathom how people can know God and then preach that such an insane attack was his will. Something went seriously wrong with their theology.