I won't go up to the observation deck. The 9/11 attacks are too close to home for me. I saw the towers burning on that day. I'd been to the observation deck in the Twin Towers some years before (and two weeks before the first WTC attack in February 1993), and I was also down at the site two months after 9/11, where I saw the devastation first-hand. Did you also see the memorial fountains? They're built on the footprints of the Twin Towers. They're very humbling.