At one point I noticed my neighbor out in her backyard, and went out to tell her the news in case she hadn't heard. She hadn't. I remember she asked, "But the buildings are still standing, right?" and I answered, "Well, of course they're still standing. It's not like planes could knock them over-- could they?" I honestly couldn't conceive of something as huge as the World Trade Center towers falling or collapsing. It just didn't seem possible when they did in fact collapse.