The Kola Superdeep Borehole

The deepest hole anybody has ever drilled into the Earth: 12,262 metres straight down, reached in 1989 on the Kola Peninsula. Drilling stopped for good in 1992 at 11,882 m on a fourth attempt because the rock was 180 C, far hotter than predicted, and behaved like plastic. What they found upended expectations. The basalt layer everyone expected at 7 km was not there, just more granite. Water was circulating 3 to 6 km down and not turning to steam. The mud coming up was described as boiling with hydrogen. And there were microscopic plankton fossils six kilometres below the surface. Funding ended in 1995, the team was dissolved in 2007, the company was wound up in 2008, and the site is abandoned and partly stripped; people still drive out to look at the capped hole. The recording of screaming souls that circulates as the Well to Hell is a hoax, and a much duller thing than the plankton.