Bathyscaphe Trieste
On 23 January 1960, she reached the ocean floor in the Challenger Deep (the deepest southern part of the Mariana Trench), carrying Jacques Piccard and Don Walsh. This was the first time a vessel, manned or unmanned, had reached the deepest known point of the Earth's oceans. The onboard systems indicated a depth of , although this was revised later to ; fairly recently, more accurate measurements have found Challenger Deep to be between and deep.
Jacques Piccard
Jacques Piccard (28 July 19221 November 2008) was a Swiss oceanographer and engineer, known for having developed underwater submarines for studying ocean currents. In the Challenger Deep, he and Lt. Don Walsh of the United States Navy were the first people to explore the deepest part of the world's ocean, and the deepest location on the surface of Earth's crust, the Mariana Trench, located in the western North Pacific Ocean.