The question of the deepest place in the world does not have a single, simple answer, as the term “deepest” can refer to several distinct types of geological features and human endeavors. The ultimate depth is found in the ocean, representing the lowest point on the Earth’s surface. Other natural features on land and structures created by human technology also represent significant plunges into the planet’s crust. Exploring these different extremes reveals the physical limits of our world and the boundaries of human exploration. The deepest points are categorized by whether they are underwater, on land, or artificially created.
The Ultimate Depth: Oceanic Trenches
The deepest point on Earth is found in the ocean, within the Mariana Trench in the western Pacific. This immense crescent-shaped depression is home to the Challenger Deep, the lowest known elevation of the planet’s surface. Modern measurements place its maximum depth at approximately 10,935 meters (35,876 feet) below sea level.
This depth is a product of plate tectonics, specifically the process of subduction, where the Pacific Plate is sliding beneath the smaller Mariana Plate, dragging the seafloor downward to create a deep, narrow canyon. The environment at the bottom of the Challenger Deep is characterized by perpetual darkness, near-freezing temperatures, and immense hydrostatic pressure.
The pressure at this depth is over 1,000 times greater than the atmospheric pressure experienced at the surface, requiring specialized equipment for exploration. Early exploration included the 1960 manned descent of the bathyscaphe Trieste, carrying U.S. Navy Lieutenant Don Walsh and Swiss engineer Jacques Piccard. Later solo missions, such as James Cameron’s 2012 dive in the Deepsea Challenger, have further mapped the basin and collected samples from the hadal zone. These missions continue to reveal unique microbial ecosystems and highly adapted deep-sea life that thrive despite the crushing conditions.
Depths Below Sea Level: Terrestrial Extremes
The deepest natural points on land and in landlocked water bodies represent impressive vertical extremes. The lowest exposed land surface on Earth is the shore of the Dead Sea, a hypersaline lake situated in the Jordan Rift Valley. The Dead Sea’s surface is roughly 439 meters (1,443 feet) below sea level, making its shores the lowest land-based elevation accessible to humans.
A far greater terrestrial depth exists beneath the ice sheets of Antarctica. A canyon under the Denman Glacier in East Antarctica reaches more than 3,500 meters (11,500 feet) below sea level, though this point is completely filled with ice. This subglacial trough is the deepest point on the Earth’s continental landmass, representing a geological low point buried beneath miles of ice.
Lake Baikal in Siberia is the world’s deepest continental body of water. This ancient rift lake has a maximum depth of 1,642 meters (5,387 feet), making its floor lower than the deepest point of any other lake. The deepest known natural vertical shafts on land are found in caves, such as Veryovkina Cave in the Caucasus mountains, which plunges to a confirmed depth of 2,209 meters (7,247 feet).
Man-Made Exploration: Drilling and Mining Limits
Human curiosity has led to the creation of artificial depths. The deepest hole ever drilled for scientific purposes is the Kola Superdeep Borehole, located on the Kola Peninsula in Russia. This project, which began in 1970, reached a depth of 12,262 meters (40,230 feet) in 1989.
The primary challenge that prevented further drilling was the unexpectedly high temperature gradient within the Earth’s crust. At its maximum depth, the borehole encountered temperatures of 180°C (356°F), which caused the drilling equipment to fail and the rock to behave with plasticity. The Kola Borehole has been surpassed in total measured length by modern oil and gas wells, though these are not vertical shafts.
The deepest points accessible to humans for operational purposes are the world’s deepest mines, primarily gold and platinum operations in South Africa. The Mponeng Gold Mine is one of the deepest operational mines, with working levels that reach close to 4 kilometers (2.5 miles) beneath the surface. These mines represent the deepest locations where human beings routinely work, demonstrating the technological capacity to excavate and sustain life under immense pressure and heat.