The Mariana Trench reaches roughly seven miles below the ocean surface.
Notes on verification
Well-corroborated by multiple independent, reputable sources (Live Science, Smithsonian Ocean, Wikipedia/NOAA data). Exact figure is closer to 6.8 miles, but 'roughly seven miles' is a commonly used and reasonable approximation. [cascade flags: aggregator_dropped_primary_exists,wikipedia_dropped_other_sources_exist | tier=unverified indep_score=0.5 clusters=1 claim_tier=everyday] [kind-backfill 2026-09-16: kind=empirical eligibility=high] [harvest 2026-09-25: +4 source(s) on new hosts; tier unverified->silver indep=1.0 clusters=3]
Sources
- The Pacific Ocean—facts and information (seed:science_and_space)
- https://ocean.si.edu/planet-ocean/seafloor/mariana-trench (corroboration)
- https://www.fisheries.noaa.gov/pacific-islands/habitat-conservation/mariana-trench-marine-national-monument (corroboration)
- https://www.britannica.com/place/Mariana-Trench (corroboration)
- https://www.scientificamerican.com/article/the-mariana-trench-is-7-miles-deep-whats-down-there/ (corroboration)
- https://www.ncei.noaa.gov/news/planet-postcard-mariana-trench (corroboration)