The Grateful Dead were a rock and roll band that formed in San Francisco in the mid-1960s. The band developed a loyal cult following (known as "Deadheads") who would follow the group from concert to concert. Unlike most popular groups, the Grateful Dead were not known for selling records or radio airplay, but for their marathon concerts. These shows were remarkable for their highly improvisational quality--the band would typically not go on stage with a set program of songs, but would collectively improvise and segue from one tune to the next. The band played regularly until 1995, when guitarist, singer and nominal leader Jerry Garcia died of heart failure while undergoing drug rehabilitation.