The Altamont Speedway Free Festival took place in December 1969 and was attended by over 300,000 people. Although the event, heavily attended by Hells Angels members, infamously descended into mayhem and violence, the lineup was incredible, featuring performances by The Rolling Stones, Grateful Dead, Jefferson Airplane, Crosby Stills & Nash and more. 

Now, previously unseen footage of the concert has been shared for the first time by Britain’s Library of Congress. The footage comes from archivist Rick Prelinger’s 200,000-reel collection that was given over to the Library this year and found on “two reels of silent 8mm reversal positive – a common home movie format” which was accompanied by a handwritten note that read “Stones in the Park,” according to the library’s Head of Moving Image Section, Mike Mashon. 

While footage of the event has previously appeared in the Maysles Brothers’ documentary Gimme Shelter, this latest glimpse has never been seen before. The video comes without audio, but captures priceless performances by the Rolling Stones, CSNY and more, performing live with Hells Angels guarding the stage, as well as showing them hanging out in the crowd. Watch below.

“When I saw that, I immediately thought that it could be a home movie of the July 5, 1969, Rolling Stones Hyde Park concert held in London a couple of days after the death of guitarist Brian Jones,” Mashon wrote. “But it could also be a copy of a documentary of the same name, which would make the discovery considerably less interesting.”

“Regardless, I sent the reels up for 2K digitization by our film preservation laboratory. A couple of days later, I heard from some very excited colleagues that the scan wasn’t the Hyde Park show. It was from the Altamont Speedway concert in California and it definitely wasn’t footage from the 1970 documentary. Many people know the Gimme Shelter documentary pretty well, but there’s a lot more in this home movie.”

READ MORE: WATCH THE ROLLING STONES’ SEARING 'SYMPATHY FOR THE DEVIL' LIVE DEBUT FROM 1968

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