Dadaism.

Dadaism first appeared durin and in the aftermath of World War 1. People were angry about the fact that over 10,000,000 people had been killed and some people didn't agree with standing about and watching it happen. Obviously it is hard for a group of citizen people to stop an event such as World War 1 but people wanted to make there opinions heard, and some people, starting in Barcelona, Zurich and New York and then also in Berlin, Cologne and Paris, began a movement they called Dada. 

They believed that the fact that people who were seen as 'sane' or 'rational' stood by and didn't say anything about so much life lost was the reason such things were able to happen and they made art that was the opposite, it was insane and irrational. It was completely unusual and unlike anything a lot of people had ever seen before. Especially calling its self art. Often it didn't have any meaning, just like the name Dada, which has no particular meaning. Dada in French is a childs rocking horse, in Slavac it means yes, yes. 

Famous works of Dada art are Meret Oppenheim's Fur Covered Teacup, Marcel DuChamp's bicycle wheel stool and Hannah Hoch's photomontages.