From what I've heard Pete found an obscure spiritual and suggested to Martin Luthur King that "We Shall Overcome" might be a good song for the freedom movement.

Pete Seeger helped popularize the 12 string guitar. And invented the long neck banjo as mentioned before.

Pete also appeared before the HUAC and stood his ground.

Everyone somewhere in the world knows and loves a song that Pete Seeger had his hands on. The evidence is clear on that.

Easily one of the most influential musicians of the 20th Century.