Welcome to The Deepest Hole on The Entire Planet

Deep in western Russia, if you know where to look, you will discover a small group of dirty scrap metal and broken concrete. Which is not that stimulating. But if you rifle through the rubble, you will discover a big metal disc bolted to the ground. This is not just any old disc – it is the welded-shut cap of a borehole that drops more than 12 kilometers (7.5 miles) into the Earth. How deep is 12 kilometers, comparatively? Deeper than the deepest point of the ocean - the Mariana Trench. In fact, this is the deepest hole we've ever dug into our planet.