I lived on London Street at the time, I was about 13.
I was coming home from a store and had just turned right from Persia Avenue onto London Street.
I had gone about 50' when something made me turn around.
Above London Street, and I would guess at an altitude of about 1,000', was this round bright white light.
It wasn't bright enough to cause me to cover my eyes, but kept me watching.
There were no blinking lights, no sound and being one block from Mission Street, a very busy street, it was strange that there were no street noises.
I watched this light for about 15 minutes, when it dipped slightly on the southwestern side of the object and headed out.
It disappeared in a matter of seconds.
I went home, told my mother about it and I went to our kitchen window which faced toward Mount Davidson and to the West.
I could again see 2 bright objects, the same type I had seen about 10 minutes before, head from South to North, the around Twin Peaks, head due West where they disappeared from sight.
That has been my only encounter with a UFO.