The Altamont Free Concert, held in December 1969 at the Altamont Speedway in Northern California, was intended as a West Coast version of the Woodstock Festival. The Rolling Stones headlined the event, which featured multiple bands, including Jefferson Airplane and Santana. As many as 300,000 people attended, but the atmosphere quickly soured amidst a mix of drugs, overcrowding, and a lack of proper security measures. The Hells Angels, hired as security members, were known for their aggressive behavior and played a contentious role in maintaining order at this unregulated event.

In the chaotic moments during the Stones' performance, Meredith Hunter, an eighteen-year-old attendee, was stabbed by Hells Angels members. Reports indicate that Hunter had been brandishing a revolver, which prompted the guards to react violently. Video footage captured the incident, and it became emblematic of the darker side of the counterculture movement of the 1960s. The event's descent into violence shattered the idealized notions of peace and love that were often associated with this era.

Following the concert, media coverage focused on the violence and the deaths that occurred, contrasting sharply with the previous festival experience at Woodstock just a few months earlier. The Altamont incident highlighted the challenges of managing large gatherings and the risks involved with such unsanctioned events. The cultural shift reflected in the tragedy became a key point in the evolution of rock music as a legitimate industry, influencing both concert security protocols and perceptions of live music gatherings moving forward.