Challenger Deep

If Mount Everest were set down in the Challenger Deep, its summit would still lie about two kilometers under water. This narrow slot in the floor of the western Pacific is the deepest known point on Earth, close to 11 kilometers below the surface, where the water pressure is more than a thousand times that at sea level and the temperature hovers just above freezing. Sunlight never reaches it. Even so, amphipods, sea cucumbers and microbial mats live in the darkness, and divers have spotted plastic litter on the bottom. For more than half a century only two people had ever been there. The number has since grown into the dozens, but the Deep remains one of the least visited places on the planet.

The Challenger Deep lies at the southern end of the Mariana Trench, about 300 kilometers southwest of Guam, in waters under the jurisdiction of the Federated States of Micronesia. It is not a single pit but a narrow depression made of three basins, each roughly 6 to 10 kilometers long and 2 kilometers wide, lined up west to east across about 48 kilometers of trench floor. The trench marks where the Pacific Plate dives beneath the smaller Mariana Plate, along the Ring of Fire. Measured depths vary with method and basin. A 2021 analysis put the deepest point at 10,935 meters, give or take 6, in the eastern basin, while direct pressure readings from submersibles cluster between about 10,910 and 10,930 meters.

The British survey ship HMS Challenger first sounded this part of the trench in 1875, and its namesake HMS Challenger II pinned down the record depth in 1951, giving the Deep its name. On January 23, 1960, Jacques Piccard and US Navy lieutenant Don Walsh rode the bathyscaphe Trieste to the bottom and spent about 20 minutes there in a cloud of stirred-up silt. No one returned until filmmaker James Cameron's solo dive in 2012. Since 2019 the privately built submersible Limiting Factor and China's Fendouzhe, which first reached the bottom in 2020, have carried dozens of people down. Scientists study the Deep to learn how life copes with crushing pressure and how trenches trap carbon and pollutants.

• Point Nemo
  The oceanic pole of inaccessibility, the point in the sea farthest from any land another ocean extreme
• Mount Everest
  Earth's highest mountain, the crown of the Himalaya on the Nepal-Tibet border deeper than this peak is high
• The Tectonic Plates
  The seven great slabs and dozens of smaller ones that make up Earth's moving shell formed by
• Federated States of Micronesia
  Four island states across the western Pacific in the waters of
• Micronesia
  Two thousand tiny islands scattered over an ocean located in
• Pacific Ocean
  Earth's largest and deepest ocean located in
• Dead Sea
  A hypersaline lake at the lowest point on Earth's land surface lowest point on land
• The Ring of Fire
  The Pacific rim of subduction, where the ground does not hold still part of