Dadaism was an early 20th century avant-garde art movement founded in Zurich that rejected reason and logic in favor of irrationality, chaos and nonsense. It began as a reaction to World War I and the nationalism and rationalism that had led to the war. Key figures included Hugo Ball, Richard Huelsenbeck, Tristan Tzara, Marcel Duchamp, Max Ernst, Francis Picabia and Raoul Hausmann. Their works featured found objects, collage, photomontage and absurdist performances designed to shock audiences. Dadaist art rejected cultural norms and emphasized anti-art, chance, nonsense and irrationality through provocative works that undermined traditional notions of art.