<a href="https://en.wikipedia.org/wiki/Bathyscaphe_Trieste" class="extiw" title="w:Bathyscaphe Trieste">Bathyscaphe Trieste</a>, a Italian-built deep-diving research submersible vehicle, which with its crew of two reached a record maximum depth of about 10,911 metres (35,797 ft), in the first descent of the deepest known part of the Earth's oceans, the <a href="https://en.wikipedia.org/wiki/Challenger_Deep" class="extiw" title="w:Challenger Deep">Challenger Deep</a>, in the Mariana Trench near Guam in the Pacific, on 23 January 1960.  It is being hoisted out of the water in a tropical port, circa 1958-59, soon after her 
 purchase by the US Navy.  The craft consists of a 2 meter spherical steel pressure vessel constituting the 2-man crew cabin, made to withstand the extreme pressure  suspended below a large tank of gasoline making up the bulk of the vessel.  The gasoline being lighter than water makes the craft buoyant, while its incompressibility withstands the pressure of the surrounding water without requiring a heavy pressure vessel.
Unknown author<span style="display: none;">Unknown author</span>
between 1958 and 1959 <div style="display: none;">date QS:P,+1958-00-00T00:00:00Z/8,P1319,+1958-00-00T00:00:00Z/9,P1326,+1959-00-00T00:00:00Z/9</div>
Retrieved from  <a rel="nofollow" class="external text" href="https://www.history.navy.mil/content/history/nhhc/our-collections/photography/numerical-list-of-images/nhhc-series/nh-series/NH-96000/NH-96801.html">NH 96801 U.S. Navy Bathyscaphe Trieste (1958-1963)</a>, Art collection, U.S. Naval History and Heritage Command website.   Released by the U.S. Navy Electronics Laboratory, San Diego, California.