A happening is an event, whether artistic or not, that unfolds more or less spontaneously and involves more or less improvised participation from the public. The term is generally associated with the American artist Allan Kaprow, who launched the “Happenings” art movement in 1957, characterized by a subversive spirit. In the field of event communication, a happening is often distinguished by its surprising, even provocative, nature.

On September 17, 2011, the Adbusters association organized a happening on Wall Street in Manhattan, New York, to denounce financial speculation, corruption, and moral issues in general.