 He spent more than three hours exploring the ocean floor, becoming the first to accomplish the trip alone.During his dive to the Challenger Deep, he discovered new species of sea cucumber, squid worm and a giant single-celled amoeba.He was preceded by unmanned dives in 1995 and 2009, as well as by Jacques Piccard and Don Walsh, the first men to reach the bottom of the Mariana Trench aboard the Bathyscaphe Trieste in 1960.