Some experts believe that our knowledge of space is now greater than our understanding of what exists beneath the Earth’s surface. And while we all remember the space race that took place between the United States and the Soviet Union during the Cold War, only a few people remember the equally fascinating battle to conquer the subterranean world. Beginning in the late 1950s, American and Soviet scientific teams started experiments in order to penetrate the centre of the Earth. The dense surface, that goes up to 50 kilometers into the centre of our planet, eventually gives way to a mysterious inner layer that makes up 40% of the Earth’s mass.
