Video Courtesy: New York Police Department
New video of the September 11, 2001 attacks, from a police helicopter hovering near the burning World Trade Center towers in the hope of rescuing survivors from the rooftops. The video is part of a cache of information from the attack handed over by city agencies to the National Institute of Standards and Technology (NIST), the federal agency that investigated the collapse. Only police helicopters were allowed in the airspace near the skyscrapers, and the officers were the only ones shooting images from above.