Imagine reveals the darker side of one of Britain's most original and inventive artists. A sculptor working with found materials, Cornelia Parker creates beauty from acts of brutality - an exploded shed, piles of squashed silver, the charred remnants of a burnt church suspended in time. Born in 1956 to a German mother and an English father in rural Cheshire, Parker always struggled to fit in. Art was her escape. In 2016 she embarked on the most high-profile commission of her career - the roof of New York's Metropolitan Museum of Art. Alan Yentob follows Parker's creative process in a film that sees her delve deep into America's history, cinema and art, as well as her own personal past.