Chinese President Xi Jinping (4th R), also general secretary of the Communist Party of China Central Committee and chairman of the Central Military Commission, learns details of underwater glider "Haiyi" and deep-sea lander "Tianya" at the Institute of Deep-sea Science and Engineering of the Chinese Academy of Sciences, in Sanya, south China's Hainan Province, April 12, 2018. Xi made an inspection tour in Sanya on Thursday. [Photo/Xinhua]