It's a sad and powerful portrait of the woman who, along with Abraham Lincoln, may have been the most American of Americans, embodying everything wonderful and everything horrible about our society.
Put together only a few years after her death, this has some amazing interview subjects - schoolteachers, her first husband ("I knew Norma Jean, I never met Marilyn Monroe."), and even her foster parents. It's all narrated by John Huston, who directed her breakthrough and her final, breakdown performance. He had a fascinating relationship with her, which if you're interested, you can read up on in Jeffrey Meyers's biography John Huston: Courage and Art, a book that's very good when it stops trying to be great.
The youtube version of The Legend of Marilyn Monroe is bookended by some interesting interviews with the filmmakers decades later. Check it out!