Dadaism is a post-World War I cultural movement (1916-1923) in visual art and literature that emerged as a rebellion against the horrors of war and the rigid intellectualism in society. Founded by artists like Tristan Tzara and Marcel Duchamp, Dadaism embraced irrationality and chaos, challenging conventional definitions of art and introducing concepts like 'anti-art'. The movement significantly influenced later art movements, such as surrealism, and is characterized by a lack of rules, emphasizing that 'the idea is more important than the work itself.'