RADIO DISPATCH TAPES: These are tapes of radio transmissions between police officers and firefighters and their dispatchers at the scene of the World Trade Center attacks on Sept. 11. The tapes cover the period just before the first tower collapse at 10 a.m. through the second collapse and the chaotic aftermath.

TAPE NO. 1 Planes have crashed into both towers and the tape picks up minutes before the collapse of the first tower and the response immediately after the collapse. (15 minutes)

TAPE NO. 2 After the first tower collapse, there were reports of people stranded under the World Trade Center. (4 minutes)

TAPE NO. 3 Before, During and After the Second Tower collapse. (9 minutes)

TAPE NO. 4 THE SEARCH AND RESCUE EFFORT - As calls come in from people, officers and firefighters trapped, emergency services workers try to keep them calm as they pinpoint locations. Tape includes call for help from Capt. Fuentes who was pulled alive from the wreckage. (9 minutes)