Dada
This was a movement that threw the uselessness of a “beautiful painting” in the face of mass death. In 1916, people who had fled the war gathered in neutral Switzerland, in Zurich, and opened a club called the Cabaret Voltaire. The way they picked a name suits them. It is said they stuck a paper knife into a dictionary and took whatever word the blade landed on. Dada — French for a child's hobby horse. It means nothing. They chose meaninglessness on purpose. On this map, a style's name is usually an insult handed to it from outside. Dada is one of the rare cases that named itself — but the way it named itself was itself a refusal: a refusal to let a name mean anything at all. Years later, Tzara and Huelsenbeck argued over who had actually coined it — a fight over ownership of a meaningless word. I doubt there is a more Dada footnote than that. Then in 1917, Duchamp signed a urinal ‘R. Mutt’ and submitted it to an exhibition that was supposed to accept anyone who paid the entry fee. It was rejected anyway. That single gesture turned the question “what is art?” into the artwork itself, and it reached straight through to conceptual art half a century later.