China's manned submersible Shenhai Yongshi (Deep Sea Warrior) returns to the oceanic research vessel Tansuo-1 in South China Sea, May 20, 2018. The submersible Deep Sea Warrior returned to the oceanic research vessel Tansuo-1 on Sunday morning after carrying out a night dive of about 1,400 meters deep in the Haima Cold Seep area in the Pearl River mouth basin in the South China Sea. (Xinhua/Zhang Jiansong)