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.
Maurice Fargues
In September 1947, just before the "Salon Nautique" in Paris, Cousteau insisted to organize a series of deep diving attempts to determine the maximum depth a scuba diver could reach. On September 17, Maurice Fargues made the first deep diving attempt near the French Navy base at Toulon. Maurice Fargues descended an anchor line with marker slates attached at 10 metres intervals, allowing him to sign his name on them to certify the depth he had reached, and periodically tugged on a safety line attached to his weight belt to let his colleague Frédéric Dumas on the surface know that he was alive. After three minutes, at a record-setting depth of , Maurice Fargues stopped signalling. Philippe Tailliez ordered that he be pulled up, and Jean Pinard dove to meet him at 60 meters depth, only to discover that Fargues was unconscious, his mouthpiece hanging on his chest. Resuscitation attempts were continued for twelve hours, but Fargues was dead. Nitrogen narcosis or oxygen toxicity had caused him to lose his mouthpiece and drown.