The Dada art movement began in Zurich during World War I as a rejection of prevailing standards in art through anti-art works. Dada was anti-aesthetic and intended to have no meaning, instead provoking interpretation from viewers. Notable Dada artists included Hans Arp, Marcel Duchamp, Francis Picabia, Hugo Ball, Max Ernst, and Man Ray. Duchamp challenged artistic conventions by declaring a urinal a work of art titled "Fountain" and used pseudonyms like "Rrose Selavy" in some of his works.