When I see a picture of Pete, I see both an average, nothing-special-about-him human being and a man filled with intensity, commitment and passion.
The first disarms you. The second grabs you and is what makes Pete "dangerous" and effective at what he did so well- sing, get others to sing, and finally to make a difference in the world.
He took Woody Guthrie's music, the folk music of rural America, and his own talent and brought about the "folk revival" that still is a staple of American music. He accomplished that with the Weavers, hitting the Top 10 and taking their music into places that were certainly not used to that style- night clubs and concert venues.
Here's a link to Smithsonian Folkways Tribute to Pete.
In 1958, Pete wrote a song for the funeral of a friend. He said he had no suitable song, so he wrote one. The song was used at the end of the Emmy-award winning PBS documentary, Pete Seeger: The Power of Song.
From the Albany, NY Times Union:
The final song Pete Seeger heard in a New York City hospital as he died peacefully of natural causes on Jan. 27 at 94 was "To My Old Brown Earth," which he wrote in 1958.
Singer-songwriter Pat Humphries led a sing-along with a few close friends and Seeger's family, who held his hands and encircled his bed. They sang:
To my old brown earth
And to my old blue sky
I'll now give these last few molecules of "I."
And you who sing,
And you who stand nearby,
I do charge you not to cry.
Guard well our human chain,
Watch well you keep it strong,
As long as sun will shine.
And this our home,
Keep pure and sweet and green,
For now I'm yours
And you are also mine.