Peter Paul and Mary, durable folk group

I'm making this page about Peter Paul and Mary because it was not without reason that Peter Paul and Mary are known as the most popular folk group of the 60's and one of the most durable music acts in history. I think Peter Paul and Mary have the best harmony of any singing group ever and their unique sound was best suited for their specialized genre, folk music.
It happened sort-of by accident, as the 3 of them came separately to Greenwich Village in the 60's during the folk revival, and someone suggested they try singing together. The rest is folk music history. They became leaders of the folk revivall of the 6o's, popularizing many folk songs with their unique folk style.
Peter, Paul and Mary, of course, helped invent "protest" music when they recorded Bob Dylan's "Blowin' in the Wind," transforming it into a '60s civil rights anthem. Their music helped lead the way in the Civil Rights movement of the 60's, as they joined the march on Washington.
Peter Paul and Mary are the most enduring of the folk groups. Their great sound has been enjoyed by every generation since their inception and they are still popular today in many circles. They have done several reunion concerts for PBS and have kept on making new albums.