SANSHA, CHINA - JULY 24:
A marine expert jumps into the Sansha Yongle Blue Hole to do exploration on July 24, 2016 in Xisha Islands, Sansha City, Hainan Province of China. Sansha municipal government has named the world\'s deepest ocean blue hole as \"Sansha Yongle Blue Hole\" which is located around the Yongle atoll of the Xisha Islands. The hole has a vertical depth of 300.89 meters, a diameter of 130 meters on the surface, and its bottom\'s diameter is 36 meters. No connection between the hole and the outside sea has been found so far and the water inside the hole has no obvious flow.