Before digital computers, the Mellotron was the world's first 'sampler.' Inside this heavy keyboard were dozens of magnetic tape strips, each about eight seconds long. When a player pressed a key, a playback head would engage the tape, playing a recording of a real instrument—such as a flute, cello, or choir. When the key was released, a spring would pull the tape back to the start. This allowed rock bands in the 1960s and 70s to have orchestral sounds on stage without a full orchestra. The most iconic use of the Mellotron is the flute introduction to 'Strawberry Fields Forever' by The Beatles. It was also a cornerstone of Progressive Rock, used extensively by bands like King Crimson, Genesis, and Yes to create symphonic soundscapes.