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 ...

The deepest man-made hole on Earth is no longer a gaping wound in the Arctic rock but a quiet, sealed scar. Once hyped as a literal “entrance to hell” in feverish urban legends, the Kola Superdeep ...