There are mystical and awesome moments in history: days when entire historical streams collide and coalesce into a single pinpoint of collapse. Nov. 9, 1989: the fall of the Berlin Wall-the entire Soviet era and the Cold War, crumbling in a hail of concrete. Feb. 3, 1959: The Day the Music Died-the innocence and naivet of early rock 'n roll and the '50s burning up and crashing to earth. These are moments of myth when intangible and supernatural forces reduce to a microcosm, a specific time and place where zeitgeists materialize for an instant before shattering.

The '60s-that mythological decade of cultural madness-imploded Dec. 6, 1969 at the Altamont Speedway. There, the promise of Woodstock and the Age of Aquarius mutated into a frenzied paroxysm of violence, leaving 850 injured and four dead. From Nov. 3 through Nov. 9, the Brattle Theater will be showing a newly restored and re-edited version of Gimme Shelter-the completely enthralling and horrifying documentary that captured the day's ferocious chaos.

Among other things, the film underscores the power of documentary film to capture the unexpected. It was initially conceived of as a fairly straightforward concert/tour movie (albeit directed by the controversial masters of cinema verit David and Albert Maysles). The moment seemed ripe for such a project: in the wake of Woodstock, hippiedom was charting a hopeful course with its promise of unbridled freedom and creativity. And the Rolling Stones were touring the U.S., culminating in a giant San Francisco festival already billed as "the Woodstock of the West." More than anything else, the film seemed poised to capture the energy and passion of a generation as seen through the roaring rock 'n roll dervish that was the '69 Stones.

But things went terribly wrong. We can see hints of the impending disaster in some of the film's pre-Altamont footage: raging groupies attack Mick Jagger; backstage, suits furiously try to exploit the potential of the upcoming San Francisco concert at any expense (in one particularly chilling moment, one lawyer makes the ominous prediction, "It'll be like lemmings to the sea").

The generally slipshod, by-any-means-necessary approach to the organizing of the affair resulted in several unfortunate decisions. Most heinous was the decision to save money on security detail by giving a cadre of Hell's Angels free beer to protect the stage-a move that ultimately resulted in vicious beatings, Jefferson Airplane's lead singer Marty Balin getting knocked unconscious and one ferocious stabbing death. Some of the film's best and most chilling moments display the palpable tension as drunken bikers thuggishly stomp around the stage while vacuous tripping hippies wave their hands and the performers look particularly ill at ease. In one instance, Marianne Faithful of Jefferson Airplane dogmatically muses about "loving your brothers and sisters" while four Angels savage a listener with pool cues.

But the film does not pretend to be a judge, nor a neutral viewer. Gimme Shelter's true brilliance lies in its depth and ambiguity. The Angels are not necessarily the villains intruding on the peace-n-love vibes of the hippies. The entire dark side of '60s is on display: chaos and mindless anarchy have rushed into the void cleared by the vague promise of freedom. The audiences seen here are the dark doppelgangers of Woodstock. Every face looks programmed and every movement emotionless, like a Stepford Wives vision of the hippiedom. Along with the Charles Manson bloodbath four months earlier, Altamont revealed the antipode of Woodstock's blissed-out flower children-the negative space on the other side of the spaces of freedom that the '60s opened up.

Gimme Shelter has a lot to offer the viewer: in addition to the incredible footage of Altamont and the infamous-almost unbearably brutal-stabbing caught on film, there's great concert footage from the tour: the Stones are at their raw and gritty peak and Mick Jagger gives a clinic in stage dominance. There's even prophetic footage of Tina Turner singing a duet with Ike Turner, their voices spasmodically oscillating between pure sexuality and brutal violence. We see great backstage footage and intimate shots of the Stones in the studio recording Sticky Fingers. We see the machinations of the music industry attempting to alchemize the flailing fury of '60s rock 'n roll into cold cash. We see the Stones pensive and melancholy as they watch their own concert footage-including their own pitifully flaccid attempts to calm the crowd.

And this is what Gimme Shelter ultimately attempts to provide: a vision of us looking at ourselves, a meta-meditation on what it means to be present and what it means to watch. At once it tries to provide footage of a defining historical moment and question what that footage means. The film begins with Jagger sneering to a New York crowd, "We're gonna have a look at you. We're gonna see how beautiful you are." It's the film's mission statement, the launching pad into an ambitious documentary that draws viewers into the complex intersection of culture, music and history it presents. As such, Gimme Shelter is a haunting vision of chaos and emptiness, of a generation struggling for meaning in the sunset of the '60s.