The deepest borehole in the world — 12,262 metres, drilled between 1970 and 1992. Science got surprises out of it: water at a depth where there should be none, and microscopic fossils in rock two billion years old. Urban legend added its own: that a microphone lowered into the hole recorded screaming, and drilling was abandoned because of a well to hell. No such recording exists and the project ended when funding collapsed, but the story lives on its own.