03/04/2021 11:41 AM | Click to read full article
The Guinness World Records award for "the deepest human invasion into the Earth's crust" goes to the Kola Superdeep Borehole. Its depth is 7.4 mi. You can find it in the icy part of Russia where the winter temperature of -40°F is a common thing.
Up to the depth of 4.3 mi, the drill easily coped with granite rock. Then, denser layers came and broke the drill.