<p>For centuries we have dreamt of reaching the centre of the Earth. Now scientists are uncovering a bizarre and alien world that lies 4,000 miles beneath our feet, unlike anything we know on the surface. It is a planet buried within the planet we know, where storms rage within a sea of white-hot me<x>tal and a giant forest of crystals make up a me<x>tal core the size of the Moon.
Horiz...</p>
