This day in music history.

December 6, 1969, The Rolling Stones play a free "thank you" concert for 300,000 fans at the Altamont Speedway in Livermore, California. Also on the bill were Grateful Dead, Jefferson Airplane, Santana and Crosby, Stills, Nash & Young . In an interview before the concert Mick Jagger said "It's creating a sort of a microcosmic society.... It sets an example to the rest of America, as to how one can behave in nice gatherings". The promoter hired Hells Angels to be security and paid them in free beer. The event rapidly falls into a disaster when the Angels start beating people up with pool cues. By the time Jefferson Starship takes the stage it is so out of hand Marty Balin (lead vocalist) tells the Angels to stop the fighting so one of the Angels punchs him and knocked him out, right on stage. By the end of the concert four people would be dead, including one who was stabbed. The murder is filmed and included in the film "Gimme Shelter" which premiers exactly one year later.
Gimme Shelter by The Rolling Stones
Oh, a storm is threat’ning
My very life today
If I don’t get some shelter
Oh yeah, I’m gonna fade away
War, children, it’s just a shot away
It’s just a shot away
War, children,
it’s just a shot away
It’s just a shot away
Ooh, see the fire is sweepin’
Our very street today
Burns like a red coal carpet
Mad bull lost it’s way
War, children, it’s just a shot away
It’s just a shot away
War, children, it’s just a shot away
It’s just a shot away
Rape, murder!
It’s just a shot away
I tell you love, sister,
it’s just a kiss away
It’s just a kiss away