Some of the most creative outpourings in art history have taken place through artistic collaboration. Pablo Picasso and Georges Braque worked closely between 1908 and 1914 to forge the Cubist style, and the works staged jointly by Marina Abramović and Ulay revolutionized Performance Art in the 1970s. An artist collective is a defined group of creatives who work together towards a similar goal, united by political, economic, professional, or historical circumstances. More visible as a group, collectives offer a pragmatic way to create impact through large-scale projects and exhibitions. Many art collectives like Critical Art Ensemble, Gran Fury, and Tucuman Arde are grounded in political activism. The Guerilla Girls and Spiral, for example, are collectives that advocate for women and minorities in the arts.