Yes, humans have been to the bottom of the ocean, most notably the Challenger Deep in the Mariana Trench, with the first crewed dive in 1960 by Don Walsh and Jacques Piccard aboard the Trieste, followed by solo dives by James Cameron in 2012 and regular expeditions by Victor Vescovo in the DSV Limiting Factor since 2019. These descents, using specialized submersibles, have allowed humans to reach the deepest points on Earth and explore these extreme environments, with several individuals now having made the journey.
We can't say we've explored the seafloor until we've seen it, and explorers have seen less than 0.001% of the deep ocean seafloor — that's roughly the size of Rhode Island. Since more than 90% of the ocean is deep ocean (i.e., deeper than 200 meters/656 feet), a very large majority of the ocean remains to be explored.
In January 1960, 9 years before the first man on the Moon, the Swiss Jacques Piccard and the American Don Walsh reached the bottom of the Challenger Trench, the deepest point on Earth, aboard the Trieste at 10,916 m. And what a surprise! The two explorers saw shrimps and an as-yet-unknown flatfish.
James Cameron (Canada) made the first solo dive to the bottom of the Challenger Deep in 2012 in his Deepsea Challenger to a reported depth of 10,908 m (35,787 ft). On the 2020 expedition to the Challenger Deep, several further records were set by passengers who accompanied Vescovo on his dives.
Don Walsh (along with Swiss oceanographer Jacques Piccard) became the first person to descend to the deepest part of the ocean, the Challenger Deep in the Mariana Trench. Walsh went on to teach ocean engineering, and remains a passionate advocate of ocean exploration.
Summary: 2025 is a transformative year for ocean governance, marked by three landmark events: the UN BBNJ Convention entering into force, new WTO fisheries subsidies regulations taking effect, and the adoption of a historic political declaration at the 2025 UN Ocean Conference.
Most of the ocean remains unexplored (around 80-95%) due to its immense size, extreme darkness, near-freezing temperatures, crushing pressure (over 1,000 times surface pressure in the deep), and the high cost and technological challenges of developing specialized equipment to withstand these harsh, hostile conditions. Sunlight can't penetrate far, visibility is near zero, and deep-sea life is adapted to pressure that would crush most vessels, making direct human study difficult and expensive.
Chris Lemons survived without oxygen for nearly 30 minutes due to a combination of his body being saturated with oxygen from the heliox gas he breathed (a helium-oxygen mix) and the near-freezing North Sea water rapidly cooling his body and brain, drastically slowing his metabolism and oxygen demand, a phenomenon often called "diving stasis," though experts still call it a miracle. His tissues held oxygen reserves, and the cold reduced his body's need for it, allowing him to last until rescue, an event documented in the film Last Breath.
Jumping from a height of 20 feet (6.1 m) results in a person impacting with the water surface at 25 mph (40 km/h). Impacting with the water surface at this velocity is capable of giving a person temporary paralysis of the diaphragm, a compressed spine, broken bones, or concussion.
At the bottom of the trench at around 11,000 metres below the sea surface, the water column above exerts a pressure of 1,086 bar (15,750 psi), approximately 1,071.8 times the standard atmospheric pressure at sea level or eight tons per square inch. The temperature at the bottom is 1 to 4 °C (34 to 39 °F).
Oceans make up roughly 99.5% of the planet's habitats by volume, and within those largely unexplored depths there are thought to be scores of large marine animals unknown to science. When you consider smaller animals too, the number of unknown species rises to the millions.
The maximum depth reached by anyone in a single breath is 702 feet (213.9 metres) and this record was set in 2007 by Herbert Nitsch. He also holds the record for the Deepest no-limit freedive– reaching a depth of 831 feet (253.2 metres) but he sustained a brain injury as he was ascending.
Psalm 104:25-26 – “There is the sea, vast and spacious, teeming with creatures beyond number-living things both large and small. There the ships go to and fro, and Leviathan, which you formed to frolic there.” Psalm 95:5 – “The sea is his, for he made it, and his hands formed the dry land.”
More than 70% of our planet is ocean – and 90% of that ocean is deep sea.
With the human body not equipped to survive in water, many fatalities are recorded every year as a consequence of natural death or suspected murder. Bodies can be found not only in the ocean, but also lakes, rivers, wells, swimming pools and cisterns.
A more recent study on 287 vertical fall victims revealed that falls from height of 8 stories (i.e. around 90-100 feet) and higher, are associated with a 100% mortality [4]. Thus, a vertical falling height of more than 100 feet is generally considered to constitute a "non-survivable" injury.
Water is incompressible. So the fall ends up being pretty close to 300 ft. to concrete vs. 30 ft. to concrete. Entering the water toes-first would just mean you have broken legs as well as being dead.
The 120 Rule in scuba diving is a simple guideline for estimating your No Decompression Limit (NDL) for recreational air dives: 120 minus your depth in feet equals your maximum bottom time in minutes (e.g., 120 - 60ft = 60 min). It helps manage nitrogen absorption, keeping dives safer by suggesting shorter times at greater depths to avoid decompression sickness, but it's a conservative estimate, best for shallower dives (under 100 ft), and doesn't replace dive computers or tables for complex dives (like those using Nitrox).
Many got slightly disoriented, but thankfully without any incident. That is one of the main reasons why Stephen decided to do a VWT dive down to the bottom and wait there for Alessia's exit, to optimize her level of safety and be ready to guide her to the ascent dive line if necessary.
Type I decompression sickness (less severe)
The less severe type (or musculoskeletal form) of decompression sickness, often called the bends, typically causes pain.
In the Christopher McQuarrie-directed film, Cruise went from doing stunts in the sky to doing them underwater. For the said sequence in Mission: Impossible — Rogue Nation, the actor actually had to undergo training to be able to hold his breath underwater for six minutes.
The 7 biggest ocean mysteries scientists can't explain
It is estimated that there are over three million shipwrecks worldwide! Less than 1% of these wrecks have actually been explored. Some wrecks are actively being looked for, including the Bonhomme Richard, but many are found by accident.
The end of NASA's ocean exploration efforts likely came from a combination of factors, including budget constraints, changing government priorities, technological challenges, and possibly, the daunting nature of unexpected discoveries.