Mass meeting on People's Square in Shanghai, 5 February 1967.

An impressive list of endorsing organizations is listed on this poster:
East is Red Film Commune. East is Red United Battle Corps (Dongfanghong dianying gongshe dongfanghong lianhe zhandoudui, 东方红电影公社东方红联合战斗队)
Revolutionary Rebel Faction. United Film Corps (geming zaofanpai lianhe sheyingdui, 革命造反派联合摄影队)
Workers-Peasant-Soldiers Film Factory. Red Flag Commune (gongnongbing dianying zhipianchang hongqi gongshe, 工农兵电影制片厂红旗公社)
Beijing Film Academy Mao Zedong Communist Commune Liason Station (Beijing dianying xueyuan Mao Zedong gongzhanzhuyi gongshe zhu Hu lianluozhan, 北京电影学院毛泽东共产主义公社驻沪联络站)

Zhang Chunqiao and Yao Wenyuan are in the small photographs on the first row, attending and addressing the meeting.