50 years ago tonight (Oct 6, 1976), four senior CPC leaders during the Cultural Revolution—Jiang Qing(Madame Mao), Yao Wenyuan, Wang Hongwen, and Zhang Chunqiao—were placed under isolation and investigation.
They were later permanently expelled from the Party and designated an anti-Party clique. This marked the end of the decade-long turmoil of the Cultural Revolution and laid the political groundwork for later reform and opening up.
The photo is the only group image of the four, at their trial on Jan 25, 1981, taken by Sun Yifu.