Not sure the first but it was in the mid 1960’s. Probably Peter Paul and Mary because I’ve seen them maybe 20 times and Mary solo in a very small venue about 3 times. But I also saw most of the great MoTown groups of that era too, Supremes, Tempations, Sly and the Family Stone, Smokey Robinson and many more. Last…. I can’t remember! Haven’t gone to one in maybe 15 years. I am disabled now and very hard for me to go to concerts or movies.