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.
Diving watch
The design and actual availability of divers' watches certified for more than is not explicable solely by practical diving needs.
The diving depth record for off-shore (saturation) diving was achieved in 1988 by a team of professional divers of the Comex S.A., industrial deep-sea diving company performing pipe line connection exercises at a depth of of seawater (msw/fsw) in the Mediterranean Sea as part of the Hydra 8 programme. In 1992, a Comex diver achieved a record of of seawater in an on-shore hyperbaric chamber as part of the Hydra 10 programme. A hydrogen-helium-oxygen gas mixture was used as breathing gas. The watches used during this scientific record dives were Rolex Sea-Dwellers with a depth rating and these feats were used in advertising.
The complexity, medical problems and physiological limits such as those imposed by high pressure nervous syndrome and accompanying high costs of professional saturation diving to extreme depths and the development of deep water atmospheric diving suits and remotely operated underwater vehicles in offshore oilfield drilling and production effectively nixed the need for ever deeper non-atmospheric manned intervention in the ocean.