Two Men Reach the Deepest Point of the Ocean

On 23 January 1960, the deep-diving bathyscaphe Trieste reached the ocean floor in the Challenger Deep, the deepest known point on Earth within the southern Mariana Trench. Carrying Swiss oceanographer Jacques Piccard and United States Navy lieutenant Don Walsh, the vessel completed the culminating dive of Project Nekton, an operational program conducted by the American naval command in the Pacific near Guam. Their arrival marked the first time that anyone had reached the floor of the Challenger Deep, concluding a descent that required four hours and forty-seven minutes.

The bathyscaphe was conceived by Auguste Piccard, who drew upon his earlier work with deep-sea submersibles to develop an untethered design. In contrast to tethered diving bells, this vehicle utilized liquid petrol in its buoyancy tanks to achieve flotation, as gasoline remains lighter than seawater and compresses little under load. Water allowed into the tanks through balancing valves preserved structural integrity without requiring extreme plating thickness. To force descent, two large hoppers carried many tons of iron shot ballast held in place by electromagnets. Shutting off the current allowed the weights to drop away, ensuring that an electrical blackout would cause the vessel to resurface automatically.