Don’t just notice that it has a diameter of only 23 cm. The focus is on the unparalleled 12-kilometer depth of the Kola ultra-deep drill hole.
Russian scientists started the drilling project on the Kola Peninsula in 1970. After about 20 years of excavation and experimentation, they finally dug out the deepest hole in the world – even deeper than the deepest part of the ocean.
However, when the temperature reached 180 degrees Celsius in the deepest part of the year, the drilling tools could not continue to dig.
This drill hole has been abandoned since 2008, the hole has been closed, and nothing can enter and exit.