Trieste is a Swiss-designed, Italian-built deep-diving research bathyscaphe, which with its crew of two reached a record maximum depth of about 10,911 metres (35,797 ft), in the deepest known part of the Earth's oceans, the Challenger Deep, in the Mariana Trench near Guam in the Pacific. On 23 January 1960, Jacques Piccard (son of the boat's designer Auguste Piccard) and US Navy Lieutenant Don Walsh achieved the goal of Project Nekton.
Trieste was the first manned vessel to have reached the bottom of the Challenger Deep.[
(A bathysphere is a different craft. As its name implies it is primarily a spherical body with viewing-ports for the one or two occupants, and is lowered into the sea by winch and cable. The bathyscaphe is nearer the submarine in that its occupants control the dive and ascent from within it, but it has no propulsion machinery.)
As for living on the sea-bed (which has no daylight at all so is totally dark at ocean depths) or elsewhere away in Space go, even if it becomes possible and desirable, we'd still make a mess.