 With nine RIAA-certified gold record albums in the US, and an estimated 48 million records sold worldwide, they were one of the most popular and commercially successful progressive rock bands in the 1970s, with a musical sound including adaptations of classical music with jazz and symphonic rock elements, dominated by Emerson's flamboyant use of the Hammond organ, Moog synthesizer, and piano (although Lake wrote several acoustic songs for the group).The band came to prominence following their performance at the Isle of Wight Festival in August 1970.In their first year, the group signed with E.G.