In August 1969, half a million people converge on Max Yasgur's dairy farm in Bethel, New York, for three days of music that outgrow every plan made for them. The film cuts between full performances and the crowd that surrounds them: Richie Havens opening because no other act has arrived yet, Jimi Hendrix closing with a distorted "Star-Spangled Banner," Janis Joplin, The Who, and Sly and the Family Stone in between. Split-screen editing shows the stage and the audience simultaneously, along with the mud, the rain, the skinny-dipping, and the makeshift medical tents treating bad trips and cut feet. Interviews with local residents, festival organizers, and attendees fill in what the performances leave out, including the moment the promoters give up on collecting tickets and declare it a free concert. The traffic jams that strand cars for miles and the announcements about brown acid and lost children are left in, unpolished. The film runs long enough to let the scale of the crowd, not just the music, register as the point.