Humans first descended into Challenger Deep in 1960 in a U.S. Navy submersible.
Notes on verification
Confirmed by multiple independent, high-quality sources including USNI Proceedings and Wikipedia, consistent on date, vessel, and crew details. [cascade flags: wikipedia_dropped_other_sources_exist | tier=unverified indep_score=0.3 clusters=2 claim_tier=notable] [rescored 2026-09-15: curated origin-host map (PR #65); unclassified hosts no longer scored as aggregators]
Sources
- The Pacific Ocean—facts and information (seed:science_and_space)
- https://www.usni.org/magazines/proceedings/2020/january/first-deepest-dive (corroboration)
- https://geology.com/records/bathyscaphe-trieste.shtml (corroboration)