The Deepest Hole Humans Ever Dug

On a windswept plain in the far north of Russia there is a rusted metal cap the size of a manhole cover. Underneath it is the deepest hole human beings have ever made: a needle-thin shaft plunging more than 12 kilometers straight down, deeper than the deepest ocean trench. The Soviet Union spent 20 years drilling it in a secret race to reach the Earth's mantle. Then they stopped, sealed it, and walked away, beaten by something nobody expected. And along the way they found things that rewrote the textbooks. Chapters: 0:00 A rusted cap on the frozen tundra 1:03 The Cold War race to go DOWN 1:27 Reaching for the mantle 2:01 Why the hole is only 23 cm wide 2:44 Nineteen years, a spray of boreholes 3:32 The first surprise: deep water 4:05 Fossils six kilometers down 4:27 The boundary that wasn't there 5:29 Why they stopped: heat 6:29 The rock that flowed shut 7:28 Only 0.002% of the way to the center 8:10 The "Well to Hell" hoax, busted 8:45 The whole world under your feet Wonderling is all about the things that make you wonder. Sources: the Kola Superdeep Borehole reached 12,262 m in 1989 (drilling began 1970); halted 1992 when the rock hit ~180°C — far hotter than the ~100°C predicted — turned ductile and began to close. Finds: free water squeezed from minerals, ~2-billion-year-old microscopic plankton fossils ~6 km down, and no granite-to-basalt boundary where one was predicted. The "recorded screams" story is a debunked hoax. #deepesthole #kola #earthscience