visit to the world trade center sfwloosh you went as a terrorist. >> we went so the south tower, and i had him stick his toes up to the building and look straight up the building into the sky and get that sense of vertigo that you can only get in a city like new york. >> mccormick and biggio would face the biggest challenges of their careers. >> american airlines flight 11, a blip on terry bigfw io's radar screens was climbing through 26,000 feet and would make its last transmission to air traffic controller. >> but then 16 seconds later it goes silent. >> american 11 boston. >> boston's air traffic center terry biggio and his controllers