China's scientific research ship Tansuo-1 returned to a port in Sanya City, south China's Hainan Province, on Sunday, after completing its deep-ocean expedition to the Mariana Trench.

Aboard the research vessel was China's self-developed deep-sea manned submersible Fendouzhe (Striver), which successfully conducted 23 dives, with six exceeding a depth of 10,000 meters during the 53-day voyage that started on October 14.