Trieste carried the first people to the deepest known point in the ocean in 1960.
On 23 January 1960, Jacques Piccard and U.S. Navy Lieutenant Don Walsh descended in Trieste to the Challenger Deep in the Mariana Trench. Their dive reached roughly 10,910 metres, although later surveys have produced slightly different measurements. The descent took almost five hours.
Trieste was a bathyscaphe, a free-diving deep-sea vehicle consisting of a buoyant float and a pressure-resistant crew sphere. The float used gasoline for buoyancy, while the crew sphere protected its occupants from immense external pressure. The vessel had been designed in Switzerland and later acquired and modified by the U.S. Navy.
The dive demonstrated that humans could reach the ocean’s greatest depths and return safely. Trieste is often confused with Alvin, a later research submersible that made thousands of scientific dives but did not make the historic 1960 descent.