The depths of Earth have puzzled the scientific community for millennia. For many years, we only had access to natural holes, even though many haven't been explored until fairly recently.

The deepest hole ever dug by humans dates back to the Cold War, however, when there was a race between the superpowers to drill as far into the Earth's crust ... 6,000C (10,832F) – is another ...

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 ...