This experimental instrument is a musical icon -- it's Robert Moog's first prototype synthesizer. Synthesizers allow musicians to create unique electronically-produced sounds. Moog's solid-state synthesizer was musically superior and much more portable than earlier vacuum tube-based systems. In 1968, Walter Carlos's album "Switched-On Bach" -- performed on a Moog -- caught the public's imagination. Synthesizers have been a mainstay of pop music since the late 1960s.