With modernization construction and the policy of reform and opening to the outside world, the Party further perfected its theory and line of building socialism with Chinese characteristics. At the Thirteenth National Congress of the CPC, held in Beijing from October 25 to November 1, 1987, the Party made it clear that China was still in the primary stage of socialism. It systematically expounded the basic line of putting economic construction at the centre of its work and adhering to the Four Cardinal Principles and the reform and open policy. Shown here is the site of the congress.