In 1970, Soviet scientists began drilling into the Kola Peninsula and eventually reached 12,262 metres — creating the deepest vertical borehole humans have ever made, yet barely scratching the surface of Earth’s crust
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In nearly seventy years of deep-sea exploration, researchers compiled 43,681 submersible dive records — and found that humans have visually observed less than 0.001% of the deep seafloor, an area roughly the size of Rhode Island, according to a Science Advances study published in May 2025.
Scientists have now made the most comprehensive tally yet of deep-sea exploration — 43,681 dive records dating back to 1958 — and found that humans have directly seen less than 0.001% of the deep ocean floor, an area roughly the size of Rhode Island, leaving the vast seafloor across 66% of Earth’s surface essentially unobserved.