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.
History of underwater diving
The "Tritonia" suit was upgraded into the first JIM suit, completed in November 1971. This suit underwent trials aboard "HMS Reclaim" in early 1972, and in 1976, the JIM suit set a record for the longest working dive below , lasting five hours and 59 minutes at a depth of .