No, the Mariana Trench is far from fully explored; it remains one of Earth's least-known frontiers, with only small portions, especially the deepest point (Challenger Deep), visited by a handful of manned and robotic vehicles, while the vast majority of the trench's geology, biodiversity, and ecosystems remain a mystery.
Most of the ocean remains unexplored due to its immense size, extreme conditions (crushing pressure, total darkness, near-freezing temperatures), and the high cost and technological challenges of developing specialized equipment to withstand these hostile deep-sea environments, making exploration risky, difficult, and expensive. We know more about the surface of Mars than the deep ocean floor because it's an inaccessible, alien world on our own planet.
On 10 November 2020, the Chinese submersible Fendouzhe reached the bottom of the Mariana Trench at a depth of 10,909 m (35,791 ft; 5,965 fathoms).
Because of its extreme depth, the Mariana Trench is cloaked in perpetual darkness and the temperature is just a few degrees above freezing. The water pressure at the bottom of the trench is a crushing eight tons per square inch—or about a thousand times the standard atmospheric pressure at sea level.
The Mariana Trench is one of the least explored places on Earth. Deep enough to swallow Mt. Everest, the Mariana Trench was first pinpointed in 1951 by the British Survey ship Challenger II. Known since as Challenger Deep, it was not visited for nearly ten years.
Challenger Deep, at approximately 36,070 feet (10,994 meters). How does it compare to the height of Mount Everest? Mount Everest is 29,029 feet (8,848 meters) tall. Everest would fit completely submerged in the Mariana Trench and still have over a mile (1.6 kilometers) of water above it.
332.35 Metres Deep
Defeating the deepest recorded depths of Orcas and Dolphins, comes Ahmed Gabr. Gabr holds a Guinness World Record for the deepest scuba diving in history.
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.
More than 70% of our planet is ocean – and 90% of that ocean is deep sea.
More than 95% of the ocean is left to be discovered. Scientists say that they don't know what species live deep in the ocean or in undiscovered territory, but they say that there should be millions of species to be found.
Beneath the deep sea at nearly 10,000 meters, a Chinese-led team has discovered vibrant communities of marine creatures that survive without sunlight, relying instead on chemical reactions for energy. The groundbreaking study was published on Wednesday in the scientific journal "Nature."
We have a great deal more to learn about our ocean and what resides within it, but progress IS being made. We learn more and more each year. We continue to discover new features and creatures, clues to our past, and resources that can improve our future. But the ocean will never be fully explored.
In addition to capturing photos and video, Cameron's equipment also took sediment samples. "We did find 68 new species, most of them bacteria," he tells Melissa, "but some small invertebrates, as well, that were brought back." At the spot Cameron visited, the water pressure is more than 16,000 pounds per square inch.
The 7 biggest ocean mysteries scientists can't explain
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.”
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.
Distribution of countries according to their share of the Earth's surface. The largest countries in terms of area are Russia (3.35%), Canada (1.96%) and China (1.88%). Together they occupy about 7.2% of the Earth's surface.
Today, over 80% of the global ocean (and 50% of the U.S. Ocean) is still unmapped, with even more unexplored. One of the biggest challenges of ocean exploration is the intense pressures in the deep ocean. In addition, zero visibility and extreme cold temperatures make it difficult to explore the vast ocean.
3% of the earth's water is fresh. 2.5% of the earth's fresh water is unavailable: locked up in glaciers, polar ice caps, atmosphere, and soil; highly polluted; or lies too far under the earth's surface to be extracted at an affordable cost. 0.5% of the earth's water is available fresh water.
Climate Change. Climate change represents the fastest-growing and most intense threat facing the global ocean.
Our Biggest Stories of 2025: From Climate Politics to AI and...
The global mean near-surface temperature from January to August 2025 was therefore lower than 2024 – at 1.42 °C ± 0.12 °C above the pre-industrial average, compared to about 1.55 °C ± 0.13 °C for the year 2024.
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.
The 120 Rule in scuba diving is a simple guideline for planning no-decompression dives, suggesting 120 minus your depth (in feet) equals your maximum bottom time (in minutes) to avoid mandatory decompression stops, with examples like 60 feet allowing 60 minutes (120-60=60). While useful for shallow dives, it's a conservative estimate and doesn't account for factors like multi-day diving, Nitrox, or water temperature, making modern dive computers more precise.
Some divers skip the briefing, assume the guide will handle everything, or forget the route, max depth, or signals. Miscommunication with a buddy is also common — different expectations, different spacing, or forgotten hand signals.