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.
William Beebe
From 1930 to 1934, Beebe and Barton used the Bathysphere to conduct a series of dives of increasing depth off the coast of Nonsuch Island, becoming the first people to observe deep-sea animals in their native environment. The Bathysphere was lowered into the ocean using a steel cable, and a second cable carried a phone line which the Bathysphere's occupants used to communicate with the surface, as well as an electrical cable for a searchlight to illuminate animals outside the Bathysphere. Beebe's observations were relayed up the phone line to be recorded by Gloria Hollister, his chief technical associate who was also in charge of preparing specimens obtained from dredging. Beebe and Barton made a total of 35 dives in the Bathysphere, setting several consecutive world records for the deepest dive ever performed by a human. The record set by the deepest of these, to a depth of on August 15, 1934, lasted until it was broken by Barton in 1949.