The four members of Black Sabbath may have had little use for hippie music, but they certainly agreed with the movement's anti-war stance. "War Pigs" is their most famous political song, but it began its life as a satanic number called "Walpurgis." The label didn't love the lyrics, so they simply changed it to an anti-war song called "War Pigs." It was the height of the Vietnam War, and Geezer Butler had little trouble pouring all his anger and frustration onto the page. It's nearly eight minutes long and was never a single, but audiences latched onto the track and it became a crucial part of their live show. It remains their opening number to this day.