The bathyscaphe Trieste, the vessel that reached the bottom of the Mariana Trench

Exploring the seabed is always a very complicated challenge due to the pressure exerted by the water at great depths.

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Military submarines typically operate at depths of around 300 meters (in the case of nuclear-powered submarines). These vessels rarely descend below 600 meters to avoid damage from the pressure. However, the deepest depression on Earth, the Mariana Trench in the Pacific Ocean, reaches almost 11,000 meters in depth, at the Challenger Deep.

To descend to that depth, a very robust type of submarine was needed. The Swiss inventor and explorer Auguste Piccard began working on a project to descend to the Mariana Trench in 1937, but his plans were postponed due to World War II. Work resumed in 1945 in collaboration with the French government. Finally, in 1952, construction of a bathysphagnum ray to descend to that trench began in the Free Territory of Trieste, an independent city-state that existed in the northern Adriatic Sea between 1947 and 1954, its territory later being divided between Italy and Yugoslavia.

Germany, Italy, and Switzerland contributed the scientific instruments for the bathyscaphe, which was named after the small, short-lived country in which it was built. The bathyscaphe's first sphere was manufactured in Naples. It was first launched on August 26, 1953. After a series of tests in the Mediterranean Sea, the U.S. Navy finally acquired the vessel in 1958 and moved it to the port of San Diego, where it was fitted with a more resistant sphere, manufactured by the German company Krupp Iron Works, according to the Naval History and Heritage Command.

Once ready, the bathyscaphe Trieste was taken to the island of Guam aboard the cargo ship Santa Maria, in order to carry out the feat for which it had been designed. Finally, on January 23, 1960, the Trieste, crewed by Auguste Piccard and Lieutenant Don Walsh of the U.S. Navy, achieved its objective, descending to the Challenger Deep and breaking a world record, reaching a depth of 10,916 meters. The descent lasted 4 hours and 47 minutes, and the Trieste spent 20 minutes at the bottom of the trench. In that inhospitable place, Piccard and Walsh reported observing several fish with very flat bodies. The bathyscaphe was decommissioned in 1966 and in 1980 was transported to the National Museum of the United States Navy in Washington DC, where it is currently on display.

Last October, the YouTube channel Deconstructed published an interesting video analyzing what the bathyscaphe Trieste looked like inside and out and the enormous pressure it had to withstand during its rest in the Mariana Islands:

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Main image: Deconstructed.