If Woodstock was "three days of peace and music," the Altamont Free Concert was one night of theft, injury, and death. Held six months after the iconic festival in New York, the December 1969 concert at California's Altamont Speedway was expected to be "Woodstock West," with a stacked lineup of performers including Santana, Jefferson Airplane, and The Rolling Stones. 

But with a notorious biker gang acting as event security, the concert quickly devolved into chaos and violence, leaving four dead and several others injured, in a disaster Rolling Stone dubbed as "rock and roll's all-time worst day."

From Jefferson Airplane's performance to crowd-wide brawls, here is the story of 1969's "anti-Woodstock" concert, told through 23 photos.