The hole's depth is calculated to be around 40,230 feet, which is roughly 12,262 meters into the Earth's surface.
The quest to explore the interiors of our planet has always been a priority for scientists as they look to find answers in the depths of Earth's crust. In 1989, they achieved a breakthrough by digging the deepest hole ever—the Kola Superdeep Borehole SG-3—but soon discovered a terrifying sound coming from below, according to a report from Indy100. This mammoth drilling project took place in the Pechengsky District of Russia, near the Norway border.
The drilling was done by the Soviet Union in a bid to venture as deep into the Earth’s Crust as possible. The operations of this artificial dig project went underway in 1965 and it has been said that the digging process continued for over two decades and had attained success until 1989. It reached 12.262 km (7.61 miles) in 1989. The hole's depth is calculated to be around 40,230 feet, which is roughly 12,262 meters into Earth's surface.
Interestingly, this hole's depth is equivalent to the height of Mount Everest and Mount Fuji if they are placed on top of one another. At the same time, this hole is said to be deeper than the famous Mariana Trench, which is located in the Pacific Ocean at a supreme depth of 36,201 feet below sea level. It took the Soviets almost two decades to drill 40,230 feet, but it could only reach about one-third of the way through the crust to the mantle when the project had to be halted in 1992, when the temperature reached 180C (356F) and the machine began to melt. After the collapse of the Soviet Union, the project was put on the shelf indefinitely due to lack of funding.
This is the cap of the Kola Superdeep Borehole.
— Brian Roemmele (@BrianRoemmele) November 20, 2021
They reached 40,111 feet of depth in 1989, after nearly two decades of drilling.
One of the deepest drill holes in the world.
It was so unexpectedly hot the drilling had to stop as drill bits were melting. pic.twitter.com/iRrKzhYUmh
The two-decade-long drilling project gave us detailed insights into the depths of our planet and upon digging, it was found that the deep parts of the Earth's crust were saturated with water and microscopic plankton fossils. Apart from the scientific discoveries, there were also rumors that the deep hole had mysterious noises coming from it, with many people claiming it to be the "pathway to hell." To create more hype around this discovery, an urban legend was made popular that suggested that the sounds emerging from the hole came from people who existed down below - cynically called "hell."
In the current scenario, the Kola Superdeep Borehole SG-3 has been owned by the Russian government. However, the digging site has been visited by locals and explorers and has gone on to be labeled as a mere "tourist attraction."
After the successful expedition of the Kola Superdeep Borehole, very few countries stepped forward to explore the depths of our planet's interiors. However, a recent report from The Guardian suggested that China undertook a digging project that would see them go 10,000 meters underneath the Earth's surface for scientific purposes and also to trace possible oil and gas reserves.
Editor's note: This article was originally published on March 11, 2024. It has since been updated.