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Chikyū is a Japanese drilling ship. Its goal was to study sub-seafloor environments through the Integrated Ocean Drilling Program.
China started digging a 6.9 miles (11 km)-deep borehole in Tarim Basin in 2023.
In 2012, Chikyū set a new deep-sea drilling record by reaching a depth of 25,400 feet (7,742 m) below sea level.
The goal is to search for oil and gas. But in addition to natural resources, the project will also benefit scientific research.
The Kola Superdeep Borehole was dug from 1970 to 1992 in Murmansk, Russia. It reached depths of over 7.5 miles (12 km), making it the world's deepest borehole.
The Kola Superdeep Borehole goes deep into the Earth's crust, but temperatures of over 356°F (180°C) didn't allow for the drills to dig deeper and the borehole was sealed up and abandoned.
The Mariana Trench has a depth of over 6.8 miles (11 km). It gets pretty cold too, with temperatures plummeting to 34°F (1.1°C). As for the pressure, it's over 1,000 times that experienced on the atmosphere at sea level.
The Big Hole in Kimberley, South Africa, wasn't created naturally, nor was it drilled by machines. This open-pit and underground mine was actually excavated by hand.
Located in the Pacific Ocean, around 124 miles (200 km) east of the Mariana Islands, near Guam, the Mariana Trench is the deepest known point in all of the oceans on our planet.
The IceCube Neutrino Observatory in Antarctica extends over 1.5 miles (2.4 km) underground. It was built to observe Cherenkov radiation (light) as evidence of neutrinos (massless subatomic particles) as they pass through the ice.
This sinkhole is located in Aldama, Tamaulipas, Mexico. It's known as El Zacatón, and it's the deepest water-filled sinkhole on our planet.
Sadly, hundreds of African workers died while digging this diamond mine in the 1880s. The Big Hole covers an area of over 40 acres and it has a depth of over 2,600 feet (792 m).
It's believed that Xiaozhai Tiankeng formed over the course of 128,000 years.
Xiaozhai Tiankeng, also known as the Heavenly Pit, is the largest and deepest sinkhole on Earth, at 2,200 feet (670 m) deep.
From 1961 to 1966, the American government started digging a hole in the Pacific Ocean. The hole, known as Phase I, was located off the coast of Guadalupe Island, Mexico.
The goal was to to reach the Mohorovičić discontinuity, aka Moho (the boundary between the crust and the mantle of Earth). During Phase I, they reached a depth of over 600 feet (183 m) below the seafloor.
The Woodingdean Water Well in Woodingdean, England, was dug by hand from 1858 to 1862.
The observatory was built in the Amundsen–Scott South Pole Station, which is an American scientific research station.
The Kontinentales Tiefbohrprogramm der Bundesrepublik Deutschland, aka German Continental Deep Drilling Programme or the KTB borehole, was dug between 1990 and 1994.
The goal was to study the continental crust. It's main hole (there are two) reaches depths of over 5.6 miles (9 km). The KTB borehole remains the deepest borehole in the world that is still in operation.
It was not until 2007, when the NASA-funded Deep Phreatic Thermal Explorer (DEPTHX) robot reached the bottom at a depth of over 1,000 feet (over 300 meters).
The Bertha Rogers hole was dug in 1974 to look for natural gas reserves in the Anadarko Basin in Oklahoma.
At around 6 miles (9.7 km) deep, it remains the deepest borehole in the US to this day.
Veryovkina Cave in Georgia has a depth of over 1.3 miles (2 km), making it the deepest-known cave on the planet.
Also known as the "Everest of the Deep," it wasn't until 2018 that the bottom of Veryovkina Cave was actually reached by people.
Sources: (Grunge) (WatchMojo) (ZME Science)
See also: One of the biggest rivers in the world has shrunk by up to 90%
It reached a depth of 1,285 feet (391 m), which, although it's not a lot by today's standards, was a lot back then.
Sadly, the following phases never went ahead (pictured is a model of the proposed drilling platform). While they never reached the Moho Discontinuity, the project did discover the age of part of the crust.
The depths of Earth have puzzled the scientific community for millennia. For many years, we only had access to natural holes, even though many haven't been explored until fairly recently. But things changed in the 20th century, when machines allowed us to dig deep into the Earth. But how deep have we reached, really?
In this gallery, we bring you the deepest holes on Earth—both natural and man-made.
The deepest holes on Earth
From sinkholes to boreholes
LIFESTYLE Depths
The depths of Earth have puzzled the scientific community for millennia. For many years, we only had access to natural holes, even though many haven't been explored until fairly recently. But things changed in the 20th century, when machines allowed us to dig deep into the Earth. But how deep have we reached, really?
In this gallery, we bring you the deepest holes on Earth—both natural and man-made.