US Edition In the dead of the night just after Christmas 1980, the airmen from USAF Bentwaters air base went to investigate an event in Rendlesham Forest near Woodbridge, Suffolk.
The tapes are a vivid account of what they found.
The servicemen were led by Col Charles Halt, second in command at the base.
It is clear that they thought they were witnessing some type of phenomena, with descriptions of "strange" lights in sky and odd damage to pine trees 15ft to 18ft off the ground.
One of the Americans is heard to say: "I hear very strange sounds of farmers - barnyard animals. They're very, very active, making a lot of noise.
"Straight ahead. There it is again. Straight ahead. What is it? A strange small red light.
"It looks maybe half a mile further ahead. Go back to the edge of the clearing, see if we can get a look at it... the animals have gone quiet now... It is deathly calm."
He adds in hushed tones: "There is no doubt about it - it is a strange flashing red light ahead.
"I saw a yellow tinge in it too. Weird. It's coming this way. It's definitely coming this way.
"There is no doubt about it. This is weird."
Despite endless speculation, there has never been a definitive answer to what actually happened that bizarre night.
There are a number of different theories; everything from aliens landing and lights from a lighthouse at nearby Orford to a mishap which was covered up.