When Emerson, Lake & Palmer took the stage at the California Jam festival on April 6, 1974, they were riding a high wave of success following the release of their ambitious album "Brain Salad Surgery" just a few months earlier, in November 1973. This live performance is particularly noteworthy, as it features the iconic "Karn Evil 9," the centerpiece of that album, which showcased their impressive mastery of blending rock with classical influences. The Cal Jam performance attracted a staggering crowd exceeding 200,000 fans, a testament to their soaring popularity at that time. Interestingly, this monumental event was both a celebration of their musical prowess and a defining moment in the burgeoning world of progressive rock, as it was one of the first major live broadcasts of a rock concert. They truly delivered a performance that echoed through music history, reminding listeners why they were at the forefront of their genre.