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.

Humanity has sent cameras to the Moon, Mars, Venus and the outer planets, but on Earth itself there is still a larger frontier that has barely been looked at directly. A 2025 study in Science Advances has now put a number on that gap: since 1958, researchers have compiled 43,681 records of dives deep enough [...] The post 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