Performance art is art where the actions of an individual or a group at a particular place and in a particular time in front of an audience constitute the work. It is opposed to painting or sculpture, for example, where an object constitutes the work.
Although performance art could be said to include relatively mainstream activities such as theater, dance, music, and circus-related things like fire breathing, juggling, and gymnastics, these are normally instead known as the performing arts. Performance art is a term usually reserved to refer to a kind of usually avant garde art which grew out of the visual arts.
Performance art, as the term is usually understood, began to be really important in the 1960s with the work of artists such as Vito Acconci, Hermann Nitsch and Joseph Beuys, although dada provided a significant progenitor with the unconventional performances of poetry by the likes of Richard Huelsenbeck and Tristan Tzara.
Later performance art is sometimes related to body art.
The "performance" in performance art can happen in any environment. Sometimes it occurs in an art gallery, but equally it can take place out of doors in some public space.