I went to many a Day on the Green concerts in my youth also!
My best friend & I used to hang out in that park and water sculpture in SF where Bono painted ROCK & ROLL STOP THE TRAFFIC also! THE very spot! If only that free concert had taken place 10 years earlier we would've been there. My friend lived in one of the high rise apt Bldgs that overlooked the plaza and fountain. I was in a marriage with a brand new baby in 1987!