The phenomenon now known as Arena Rock was born at the California Jam – and Deep Purple were at its epicentre. In many ways, the California Jam was the equivalent of the Woodstock festival to a burgeoning generation of hard rock and heavy metal fans. The Jam took place at the Ontario Motor Speedway in Ontario, California on a hot and sunny spring day on April 6, '74. The event attracted an enormous crowd of a quarter-million people and represented a baptism of fire – in more ways than one – for Purple's 'new boys', frontman David Coverdale and bassist/vocalist Glenn Hughes, who in '73 had replaced Ian Gillan and Roger Glover, respectively, to usher in the band's socalled Mk III line-up.