Manzhouli Red International Secret Traffic Line Ruins Introduction: 20 Manzhouli Red International Secret Traffic Line Ruins were built from the 1920s to 1937 to protect communists from Manzhouli entering and exiting the Sino-Soviet border. The early leaders of our party, Zhou Enlai, Qu Qiubai, Li Lisan, Luo Zhanglong, Wu Xiuquan and other revolutionaries, all traveled to the Soviet Union and returned to China through the cover of secret communication lines. Moreover, when the Sixth National Congress of the Communist Party of China was held in Moscow, the representatives attending the meeting all passed here.