Back in the Cold War I saw a circle of lights just over the building across the street from us. The “front” light was green, and the others were all red (around 8–10 of them). It was night, so it could be a series of planes flying in formation, but they couldn’t have kept a perfect circle for so long, and besides, they didn’t seem to move. It couldn’t have been one plane either, because the lights would have formed a cross, not a circle. I stupidly thought at the time that it was a helicopter, but of course helicopters aren’t round at all when you think of it. And it was absolutely quiet, even though the lights seemed to be quite close, and not high up in the sky.
The object stood over the building for several minutes, and then flew southeast really fast (disappeared in seconds). There were no commercial planes flying in that direction at the time (they would be crossing an international border if they did). I assumed it was some sort of secret NATO spyplane that was on a special mission. We got a lot of those back then.
It was only as the years passed by and no such plane (circular, fast and completely quiet, that can stand still in mid-air) officially appeared, that I started to think that perhaps it could have been something else. To this day, I have not heard of a working human technology that could explain what I saw.