The "Top 100 Greatest Films of All Time" is a list published every ten years by Sight and Sound according to worldwide opinion polls they conduct. They published the critics' list, based on 1,639 participating critics, programmers, curators, archivists and academics, and the directors' list, based on 480 directors and filmmakers. Sight and Sound, published by the British Film Institute, has conducted a poll of the greatest films every 10 years since 1952.