As depicted in Gimme Shelter (I saw the film when it came to theatres in 1970, but I never want to see it again), one audience member, Meredith Hunter was stabbed to death by several bikers after he pulled a gun – and yes, someone caught the incident on film.  Lead male singer Marty Balin of Jefferson Airplane was knocked out cold by a Hells Angel, and Mick Jagger was punched in the face by an unruly fan shortly after his arrival by helicopter.  It was a perfect storm where simply everything went wrong – the rain and the other privations at Woodstock were nothing compared to what occurred at Altamont.