what is generally understood to be "experimental". History of the European avant-garde Beginnings In the 1920s, two conditions made Europe ready for the emergence of experimental film. First, the cinema matured as a medium, and highbrow resistance to the mass entertainment began to wane. Second, avant-garde movements in the visual arts flourished. The Dadaists and Surrealists in particular took to cinema. René Clair's Entr'acte (1924) featuring Francis Picabia, Marcel Duchamp, and Man Ray, and with music by Erik Satie, took madcap comedy into nonsequitur. Artists Hans Richter, Jean Cocteau, Marcel Duchamp, Germaine Dulac, and Viking Eggeling all contributed Dadaist/Surrealist shorts. Fernand Léger, Dudley Murphy, and Man Ray created the film Ballet Mécanique (1924), which has been described as Dadaist, Cubist, or Futurist. Duchamp created the abstract film Anémic Cinéma (1926). Alberto Cavalcanti directed Rien que les heures (1926), Walter Ruttmann directed Berlin: Symphony of a Metropolis (1927), and Dziga Vertov filmed Man With a Movie Camera (1929), experimental "city symphonies" of Paris, Berlin, and Kiev, respectively. One famous experimental film is Luis Buñuel and Salvador Dalí's Un chien andalou (1929). Hans Richter's animated shorts, Oskar Fischinger's abstract films, and Len Lye's GPO films are examples of more abstract European avant-garde films. France Working in France, another group of filmmakers also financed films through patronage and distributed them through cine-clubs, yet they were narrative films not tied to an avant-garde school. Film scholar David Bordwell has dubbed these French Impressionists and included Abel Gance, Jean Epstein, Marcel L'Herbier, and Dimitri Kirsanoff. These films combine narrative experimentation, rhythmic editing and camerawork, and an emphasis on character subjectivity. In 1952, the Lettrists avant-garde movement, in France, caused riots at the Cannes Film Festival, when Isidore Isou's Traité de bave et d'éternité (also known as Venom and Eternity) was screened. After their criticism of Charlie Chaplin at the 1952 press conference in Paris for Chaplin's Limelight, there was a split within the movement. The Ultra-Lettrists continued to cause disruptions when they announced the death of cinema and showed their new hypergraphical techniques; the most notorious example is Guy Debord's Howlings in favor of de Sade (Hurlements en Faveur de Sade) from 1952. Soviet Union The Soviet filmmakers, too, found a counterpart to modernist painting and photography in their theories of montage. The films of Dziga Vertov, Sergei Eisenstein, Lev Kuleshov, Alexander Dovzhenko, and Vsevolod Pudovkin were instrumental in providing an alternative model from that