A sea cucumber on the ocean floor at more than 5,000 meters was captured in this undated photo taken by the crew of the submersible Jiaolong and provided by the China Ocean Mineral Resources R&D Association. The Jiaolong undersea craft -- named after a mythical sea dragon -- has returned to shore after completing five test dives in the Pacific Ocean and reaching 5,188 meters during its deepest dive. [Photo/Xinhua]