Part 3/9:
Upon reviewing the available video clips, researchers noted a number of visual discrepancies that prompted speculation about the authenticity of the footage. Certain clips appeared to show objects approaching either vertically or horizontally, leading some to hypothesize that the images of planes might have been digitally inserted after the attacks. To investigate the validity of these claims, a three-dimensional computer model of the area was created, allowing for a direct comparison between the recorded footage and the official flight paths.