This is a postcard of "Media Burn," a 1975 video art piece/"happening". You can watch the whole thing here:
http://www.mediaburn.org/Video-Previ....html?uid=4574
"Original version of Ant Farm's classic video art piece examining and satirizing the media, particularly the impact of television. On July 4, Independence Day, 1975, what a TV newscaster described as a "media circus" assembles at San Francisco's Cow Palace Stadium. A pyramid of television sets are stacked, doused with kerosene, and set ablaze. Then a modified 1959 Cadillac El Dorado Biarritz, piloted by two drivers who are guided only by a video monitor between their bucket seats, smashes through the pyramid destroying the TV sets."