Photo taken on May 23, 2017 shows a sea cucumber sample collected by submersible Jiaolong in the Mariana Trench. China's manned submersible Jiaolong finished a dive in "Challenger Deep" in the Mariana Trench, the world's deepest known trench, on Tuesday. Xinhua News Agency journalist Liu Shiping descended inside the submersible along with scientists to 4,811 meters below the sea's surface. (Xinhua/Guo Songjiao)
