If you had access to a time machine, what concerts would you go back to see?

Genesis December 18, 1974 at the Century Theater Buffalo NY. We got last minute SRO tickets and sat on the stairs in the balcony. They did The Lamb Lies Down On Broadway from start to finish. Great show at a great venue. A close 2nd would be Paul Simon at the Sony Music Center in Toronto the summer of 2016. I don't know if I ever heard a better sounding or tighter performance. Honorable mention would be the Stones in June of 1975 at the Buffalo War Memorial Auditorium. They hadn't played Buffalo in years and it was pretty wild. I had never seen the Aud as packed as it was that night. Bonus was the Crusaders were the opening act.

The one that got away. In 1975 we had tickets to see Queen at Kleinhans Music Hall in Buffalo dead center 4 rows back. The concert was cancelled last minute and back then you could exchange or return tickets at point of sale. We exchanged them for Jeff Beck and John Mclaughlin at the Century Theater in Buffalo. Bad news is that I never saw Queen and personally I never cared much for their stuff after that time frame but seeing 2 guitar legends on the same night more than made up for it!