article_snippet: Scroll down for video .
article_snippet: One of the pair films, Gimme Shelter, about The Rolling Stones' Altamont Speedway concert on Dec. 6, 1969, captured on film the killing of a fan and the darkening of the hippie dream.
article_snippet: The Altamont concert was the Stones' disastrous effort to stage a festival like the Woodstock gathering a few months earlier.
article_snippet: Christo's Valley Curtain.