The Mariana Trench reaches more than 7 miles below the surface of the Pacific Ocean.
The Mariana Trench is the deepest oceanic trench on Earth and home to the two lowest points on the planet.
The crescent-shaped trench is in the Western Pacific, just east of the Mariana Islands near Guam. The region surrounding the trench is noteworthy for many unique environments, including vents bubbling up liquid sulphur and carbon dioxide, active mud volcanoes and marine life adapted to pressures 1,000 times that at sea level.
Its depth is difficult to measure from the surface, but in 2010, the National Oceanic and Atmospheric Administration used sound pulses sent through the ocean and pegged the Challenger Deep d at 36,070 feet (10,994 meters). A 2021 estimate using pressure sensors found the deepest spot in Challenger Deep was 35,876 feet (10,935 m). Other modern estimates vary by less than 1,000 feet (305 m).
As deep as the trench is, it is not the spot closest to the center of Earth. Because the planet bulges at the equator, the radius at the poles is about 16 miles (25 km) less than the radius at the equator. So, parts of the Arctic Ocean seabed are closer to the Earth's center than the Challenger Deep.
A chain of volcanoes that rise above the ocean waves to form the Mariana Islands mirrors the crescent-shaped arc of the Mariana Trench. Interspersed with the islands are many strange undersea volcanoes.
For example, the Eifuku submarine volcano spews liquid carbon dioxide from hydrothermal vents similar to chimneys. The liquid coming out of these chimneys is 217 degrees Fahrenheit (103 degrees Celsius).
Recent scientific expeditions have discovered surprisingly diverse life in these harsh conditions. Animals living in the deepest parts of the Mariana Trench survive in complete darkness and extreme pressure, said Natasha Gallo, a doctoral student at the Scripps Institution of Oceanography.
People have been exploring the Mariana Trench for more than a century:
