The Mariana Trench—also known as the Marianas Trench—is located in the western Pacific Ocean, approximately 200 kilometers (124 miles) east of the Mariana Islands. It holds the title of the deepest oceanic trench on Earth, representing one of the most extreme and least explored environments on the planet.

This massive underwater trench is crescent-shaped and stretches about 2,550 kilometers (1,580 miles) in length, with an average width of around 69 kilometers (43 miles). The deepest known point within the trench is called the Challenger Deep, a narrow, slot-shaped depression near its southern end. Challenger Deep plunges to an estimated depth of 10,984 meters (36,037 feet) (± 25 meters [82 feet]), or approximately 6.825 miles. Some unconfirmed measurements have suggested even greater depths—up to 11,034 meters (36,201 feet).

To put this in perspective, if Mount Everest—the highest point on land—were placed inside the trench, its summit would still lie over two kilometers (1.2 miles) beneath the ocean surface.

At the bottom of the trench, the water pressure is an incredible 1,086 bars (15,750 psi)—over 1,071 times greater than the atmospheric pressure we experience at sea level. Under such immense pressure, the density of water increases by nearly 5%, and temperatures remain just above freezing, ranging between 1 to 4 °C (34 to 39 °F).

Despite these harsh conditions, life finds a way. In recent years, scientific expeditions have revealed that microbial life forms thrive in this deep-sea environment. In particular, researchers from the Scripps Institution of Oceanography discovered Monothalamea, a type of single-celled organism, at a record depth of 10.6 kilometers (6.6 miles) below the surface. These findings offer valuable insight into how life can adapt to extreme pressure, darkness, and cold—conditions similar to those that might exist on other planets or moons.

In 2009, the United States government designated the Mariana Trench as a National Monument, in an effort to protect its fragile ecosystem and unique geological features. The designation covers not only the trench itself but also its surrounding waters and seafloor, ensuring that this extraordinary underwater realm remains preserved for future exploration and study.

The Mariana Trench continues to fascinate scientists, oceanographers, and explorers alike. With its mysterious depths and potential for undiscovered life forms, it stands as a symbol of the vast, largely unexplored frontiers of our planet’s oceans.