He's talking about an act of terrorism. I hate the twin towers for the way people remember it because it has stopped everyone remembering eveything else that happened, the twin towers didn't particularly effect us here, it was just America finaly getting bombed too and we'd had it for years so it was hardly even worthy of an eyebrow raise.
Now everyone forgets that for years we where fighting a gritty war on our own streets against a minority of Irish armed with semtex, and suddenly here everyone is expected to have sympathy for America who's civilians provided over 80% of the funding for the campaign going on around us before 9/11. In that sense 9/11 was a great wakeup call and helped to bring peace. Sure people died, lots of them, but that had been going on for years previously.
Sounds harsh, but when you've been so close to it (I was Londoner once, and i'm quarter Irish) and seen it so persionally you begin to loose empathy with the one that didn't effect you and steels the limelight because it became a political tool.
I feel for the people, genuinely, but I feel for a lot more people than those who died in one poxy incident.