Video: THE DEEPEST HOLE EVER DRILLED IN THE WORLD: What did the Soviets discover in the Kola Superdeep well at a depth of 12,262 meters?

[I heard about this when I was younger and very interested in earth science. Nobody has drilled a deeper hole than this. This is way beyond the depth of mines. Jan]

Here’s the video: https://www.youtube.com/watch?v=I5yh6ggSLP0