The guy who sat next to me at my C++ class was supposed to be on one of the top floors in one of the towers for a conference. Because he had this C++ class the evening of 9/10 in Kentfield, CA, his company said he could fly out one day later. That probably saved his life. Everybody from his company, other than the CEO, who was supposed to be at the conference died. His CEO survived because he couldn't find a place to park.