Motor Speedway, Ontario, CA June 4, 1974

Taken from the infamous California Jam (also known as Cal Jam), this live set is essential Black Sabbath mid-period. The music festival - co-headlined by Deep Purple and Emerson, Lake and Palmer - held at the Ontario Motor Speedway in California, on April 6, 1974. The California Jam attracted 250,000 paying music fans. The festival was well-known for the loudest amplification system ever installed and the highest paid attendance in history. It was one of the last of the original wave of rock festivals, as well as one of the most well-executed and financially successful, and presaged the era of media consolidation and the corporatization of the rock music industry.