** FOR USE AS DESIRED WITH SEPT. 11 ANNIVERSARY STORIES — FILE **Smoke billows from one of the towers of the World Trade Center and flames as debris explodes from the second tower, in this Sept. 11, 2001, file photo. In one of the most horrifying attacks ever against the United States, terrorists crashed two airliners into the World Trade Center in a deadly series of blows that brought down the twin 110-story towers. This year will mark the fifth anniversary of the attacks. (AP Photo/Chao Soi Cheong/FILE)