China's deep-sea submersible mother ship, Tansuo-1, returns to Sanya in south China's Hainan Province, Aug. 12, 2016. Tansuo-1 returned to Sanya on Friday after completing its successful maiden voyage to the Mariana Trench. The mother ship carried 60 researchers and crew as well as a 10,000-meter autonomous remote-controlled submersible, a 9,000-meter ocean-bottom seismometer and other domestically made devices. It left Sanya on June 22 for the Mariana Trench expedition. (Photo: Xinhua/Jin Liwang)
