Deep in the Arctic Circle, there’s a man-made hole that once earned the nickname “the entrance to hell.” The Kola Superdeep Borehole, the deepest hole ever drilled on Earth, reached a staggering 12 ...

Add Yahoo as a preferred source to see more of our stories on Google. The deepest hole humans have ever drilled into the Earth is just 12.3 kilometers, about 0.2% of the distance to the planet’s core.

James is a published author with multiple pop-history and science books to his name. He specializes in history, space, strange science, and anything out of the ordinary.View full profile James is a ...