Deep in the Arctic Circle, in Russia, lies the deepest hole ever dug which was once called 'the entrance to hell'. The Kola Superdeep Borehole is the deepest manmade hole, and deepest artificial ...

This makes TJBH the deepest blue hole in the world, leaving behind the 301 meters (990 feet) deep Sansha Yonga Blue Hole of the South China Sea. However, the currently measured depth is not final ...

America might have landed on the moon, but Russia drilled the deepest man-made hole on Earth. Since the early 1960s, scientists have attempted to drill down to the Earth's mantle. It took 20 years ...