Kim Jong Un, chairman of the Workers' Party of Korea (WPK) and chairman of the State Affairs Commission of the Democratic People's Republic of Korea (DPRK), visits the Beijing rail traffic control center in Beijing, capital of China, June 20, 2018. Xi Jinping, general secretary of the Central Committee of the Communist Party of China (CPC) and Chinese president, met with Kim Jong Un at the Diaoyutai State Guesthouse in Beijing on Wednesday. (Xinhua/Yao Dawei)