with his dancers and bathers. Other important impressionists were Alfred Sisley, Camille Pissarro and Gustave Caillebotte. After that threshold was crossed, the next thirty years became a litany of amazing experiments. Vincent van Gogh, Dutch born, but living in France, opened the road to expressionism. Georges Seurat, influenced by color theory, devised a pointillist technique that governed the Impressionist experiment and was followed by Paul Signac. Paul Cézanne, a painter's painter, attempted a geometrical exploration of the world, that left many of his peers indifferent. Paul Gauguin, a banker, found symbolism in Brittany along Émile Bernard and then exoticism and primitivism in French Polynesia. These painters were referred to as Post-Impressionists. Les Nabis, a movement of the 1890s, regrouping painters such as Paul Sérusier, Pierre Bonnard, Édouard Vuillard and Maurice Denis, was influenced by Gauguin's example in Brittany: they explored a decorative art in flat plains with the graphic approach of a Japanese print. They preached that a work of art is the end product and the visual expression of an artist's synthesis of nature in personal aesthetic metaphors and symbols. Henri Rousseau, the self-taught dabbling postmaster, became the model for the naïve revolution. 20th century The early years of the twentieth century were dominated by experiments in colour and content that Impressionism and Post-Impressionism had unleashed. The products of the far east also brought new influences. At roughly the same time, Les Fauves (Henri Matisse, André Derain, Maurice de Vlaminck, Albert Marquet, Raoul Dufy, Othon Friesz, Charles Camoin, Henri Manguin) exploded into color, much like German Expressionism. The discovery of African tribal masks by Pablo Picasso, a Spaniard living in Paris, lead him to create his Les Demoiselles d'Avignon of 1907. Working independently, Picasso and Georges Braque returned to and refined Cézanne's way of rationally comprehension of objects in a flat medium, their experiments in cubism also would lead them to integrate all aspects and objects of day-to-day life, collage of newspapers, musical instruments, cigarettes, wine, and other objects into their works. Cubism in all its phases would dominate paintings of Europe and America for the next ten years. (See the article on Cubism for a complete discussion.) World War I did not stop the dynamic creation of art in France. In 1916 a group of discontents met in a bar in Zurich, the Cabaret Voltaire, and created the most radical gesture possible, the anti-art of Dada. At the