The deepest hole in the world, sealed with bolts

The deepest hole in the world is sealed with bolts

In the north of the Murmansk region, amid ruined concrete structures, a rusted metal lid welded with bolts sticks out of the ground. Beneath it is a well 12,262 meters deep. The Kola Superdeep Borehole. The farthest human incursion into our own planet.

They drilled for twenty years. They started in 1970 with an ambitious goal — to break through the Earth's crust. The first kilometers progressed relatively easily. At seven kilometers they found water where, according to all textbooks, it could not exist. At a depth of nine kilometers they discovered fossilized microorganisms two billion years old. Textbooks had to be rewritten.

At twelve kilometers the hell began. The rock temperature reached 230 °C instead of the calculated 100. At such depth the stone behaved not like a solid body but like a dense plastic mass — the drill string got stuck and broke. They lost the borehole and had to start again from a branch. The most expensive and longest dead end in engineering history.

In 1994 the project was frozen. There was no money, and there was no point in drilling further either. There were still at least 15–20 kilometers to the mantle, and the technology hit a ceiling.

The paradox of the Kola borehole in scale. Twelve kilometers sounds impressive. We have penetrated 0.2 percent. If you imagine the planet as an apple — the drill didn't even get through the skin.

The borehole was welded shut. The equipment was removed. The surrounding buildings collapsed. Only the lid and the hole beneath it remain — a silent reminder that we live on a planet we know less about than the surface of the Moon.