World War II caused the destruction of humanity, images and forms. In the musical terrain, this resulted in sentimentality in song, a break with the past, attempts at reconstructing a fractured order and the optimism of pop, all of which were diverse results of a world that had been destroyed and was in reconstruction: that of the post-war period.
Musically, mass culture, which would prevail from the end of the 1950s, had already made its appearance during the 1920s and 30s with jazz, the chanson and cabaret music. Composers of the Weimar Republic, such as Kurt Weill, would draw from these genres to create works with a strong social and political commitment. After the war, the devastation would be reflected in creations that would question traditional systems. The works of Olivier Messiaen, who experienced the atrocity of the concentration camps first hand, or those of Luciano Berio, who took instruments to the limit of their possibilities, are conspicuous examples of post-war avant-garde positions. Alongside them, composers like Francis Poulenc and Benjamin Britten would look back towards the past and try to reconstruct the tonal order that had just been broken. But it was the pop genre that thrived in the collective imagination as musically characteristic of the second half of the century, benefitting from the new channels offered by industry and the media. The phenomenon of The Beatles represents the success of this trend like no other.