Notes on verification

Well-corroborated by multiple independent, authoritative sources (Wikipedia, Britannica, NOAA, CNN, History.com). Depth figures vary slightly by survey (~35,800-36,100 ft) but consistently support the ~36,000 ft rounding and the comparison to Everest's height (~29,030 ft). [cascade flags: aggregator_dropped_primary_exists,wikipedia_dropped_other_sources_exist | tier=silver indep_score=0.875 clusters=2 claim_tier=everyday]