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.
Katie Melua
On 2 October 2006, Melua entered the "Guinness Book of Records" for playing the deepest underwater concert 303 metres below sea level on the Norwegian Statoil's Troll A platform in the North Sea. Melua and her band underwent extensive medical tests and survival training in Norway before flying by helicopter to the rig.
Melua later described achieving the record as "the most surreal gig I have ever done". Melua's concert is commemorated in the DVD release "Concert Under the Sea", released in June 2007.