Twelve Kilometres Down: The Kola Superdeep Borehole
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Twelve Kilometres Down: The Kola Superdeep Borehole
In 1970, Soviet geologists began drilling straight down into the Kola Peninsula — no ore, no oil, just science and curiosity. Over twenty-four years they reached 12,262 metres, deeper than anyone has ever drilled. What they found along the way rewrote what we thought we knew about the Earth beneath our feet.
May 25, 2026 · 2:12 PM
There is a hole in the ground in northwest Russia, on a flat peninsula that juts into the Barents Sea above the Arctic Circle. It is sealed with a rusted metal disc bolted to a concrete pad. No sign. No fence. No monument. Just a cap on the most ambitious geological drilling project ever completed — the Kola Superdeep Borehole, which reached 12,262 metres into the Earth over the course of twenty-four years, from 1970 to 1994.
This episode follows the Soviet SG-3 project from its quiet start on May 24th, 1970, through the slow years of drilling at a few hundred metres per year, to the discoveries that overturned long-held models of what the continental crust actually looks like — hotter than expected, fractured rather than solid, unexpectedly wet, and carrying the fossilised traces of life at depths where nobody thought life could leave a mark. The hole was capped after funding disappeared and the heat of 180 degrees Celsius at depth defeated the equipment. The depth record, set in 1989, has never been broken.
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