1931-

American naval officer who, with Jacques Piccard, made the first and (to date) only descent to the bottom of the Marianas Trench. Descending in a submersible, the Trieste, to a depth of nearly 36,000 feet (11,000 m), Walsh and Piccard became the first people to visit and explore the deepest spot on the planet. This trip was not only record-setting, it also showed that, contrary to accepted scientific thought at the time, life existed and flourished in the ocean's furthest depths.