Futurist, surrealist, abstract artist: those are not customary descriptions of Walt Disney, yet they all fit. People who insist on pigeonholing him as a purveyor of bland family entertainment haven’t bothered to watch his movies closely, especially his work in the 1940s. Fantasia alone should silence nay-sayers who only see Disney as a commercial populist; 75 years after its debut on 13 November 1940, it remains one of the most astonishing films ever to come from Hollywood.