The Cold War race to the centre of the Earth

How much do we know about what’s deep down under our feet?

During the Cold War, the US and Soviets both created ambitious projects to drill deeper into the earth than ever before. Now, new teams of scientists are hoping that modern technology will help us to go deeper. But what exactly will they find?

Find out more about the Kola Superdeep Borehole in this BBC Future article.

Video by Irina Sedunova