Pop art emerged in Britain and the United States in the mid-1950s, when artists began treating the imagery of mass culture - advertising, comics, product packaging, film stars and consumer goods - as legitimate subject matter for fine art. London's Independent Group debated the aesthetics of mass media; across the Atlantic painters and sculptors turned the same material into cool, bold, deliberately impersonal pictures, often borrowing commercial techniques such as silkscreen printing and Ben-Day dot reproduction. Pop art answered the emotional grandeur of Abstract Expressionism with irony, deadpan flatness and everyday icons, and in doing so collapsed the long-standing barrier between high and low culture. Its strategies of appropriation and mechanical reproduction reshaped art after 1970 and still frame how artists deal with advertising, celebrity and the image-saturated world.