The robotic arm of China's manned submersible, the Jiaolong, was seen in operation in this undated photo provided by the China Ocean Mineral Resources R&D Association. The plastic box beside it contains the polymetallic nodules it collected from the ocean floor. 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]