China’s manned submersible Jiaolong has completed a dive at Challenger Deep, the deepest known point in the world’s oceans. The journey deep into the Mariana Trench in the western Pacific Ocean lasted around nine hours. Scientists’ main tasks included testing Jiaolong’s technical equipment, and collecting samples of sea water and deep-sea life. A further four dives in the trench will see the submersible reach depths of up to 6,700 meters.