The Mariana Trench Is Deeper Than Everest Is Tall

The scale of our planet's oceans is so immense that if you could place Mount Everest at the bottom of the Mariana Trench, its summit would still be submerged by over two kilometers of water. This lowest known point on Earth, a small valley at the trench's southern end called the Challenger Deep, is a realm of extremes. The pressure there exceeds 1,000 times that at sea level, which is comparable to the weight of 50 jumbo jets pressing down on a single person. It is a world of perpetual darkness and near-freezing temperatures, one of the most inhospitable environments imaginable.

This colossal feature was carved by the slow, powerful process of plate tectonics. The trench marks a subduction zone, where the massive Pacific Plate is being forced to slide beneath the smaller Mariana Plate. As the Pacific Plate bends and plunges into the Earth's mantle, it creates this deep scar in the ocean floor. The trench was first sounded in 1875 by the HMS Challenger expedition, which gave the deep its name, but its true, staggering depth wasn't fully realized until decades later. Despite the hostile (Review) conditions, uniquely adapted life, such as the ghostly Mariana snailfish and giant amphipods, thrives in this high-pressure world.