Abel Gance's great film Napoleon, as heroic in ambition as its subject, opened at the Opera de Paris in April 1927. It was the summation of the silent cinema, a remarkable feat of imagination, ingenuity and stamina. Years in the planning and months in production, the film astonished its audience with the boldness of its conception - not least at the moment when the screen expanded to reveal Gance's visionary invention of Polyvision, a wide-screen system thirty years ahead of its time. Yet Gance's triumph was to be short-lived. The American version, re-edited by MGM, was a disaster. The sheer length of the film, and its spectacular effects, produced problems for exhibitors. Gance never gave up trying to 'improve' it. In 1934 he added sound; in 1970 he was still editing.