On Saturday 6 December 1969, some 300,000 people turned up for a free Rolling Stones concert at a speedway track near San Francisco called Altamont.
While Woodstock, four months earlier, had been the zenith of the hippie dream, Altamont marked its nightmarish nadir after an 18-year-old black man, Meredith Hunter, was murdered by a Hells Angel mere feet away from the spot where Mick Jagger was singing Under My Thumb.
The Hells Angels – who had been hired by Sam Cutler, the Stones road manager (for five hundred dollars worth of beer,) as security guards for the free show – also beat hundreds of concert-goers within inches of their lives.
They were accessorised with brass knuckles, knives, and leaded pool cues.
The crowd, having sat through sets by the Jefferson Airplane and watched the Angels beat up Marty Balin, was growing impatient for the featured act.
Finally, Mick Jagger burst upon the stage wearing gold, skintight velvet trousers, thigh-high red boots, and a red and black ruffled shirt with flowery sleeves.
The band were playing Sympathy For The Devil when suddenly there was a commotion at the foot of the stage. Then, as the Stones played Under My Thumb, a young black man in a Day-Glo green jacket made the mistake of leaning against one of the Hell Angels’ choppers.
As a pack of Angels surrounded him, he incautiously brandished a .38. Three Angels jumped him, and then he was dead, knifed in the back, neck and face.
And every hideous moment – the stabbing of Hunter included – was caught on camera, immortalised in the Maysles Brothers’ documentary Gimme Shelter.
The violence that permeated the disastrous concert was proof to many that the Age of Aquarius was over. If this truly was the dawning of a new age, it obviously had the potential to get extremely ugly.