A wall in the Xidan district in Beijing where, beginning in December 1978, in line with the party's policy of "seeking truth from facts," activists in the democracy movement recorded news and ideas, often in the form of big-character posters (q. V. ). These activists were encouraged to criticize the Gang of Four and previous (failed) government policies, but the wall was closed in December 1979 when the leadership and the communist party system were being criticized along with past mistakes and leaders. The shutdown coincided with suppression of political dissent.