Earth's mantle and core ?
Has there ever been an attempt to explore the Earth's mantle (either manned/robotic) ? There was an exploration of the Mariana Trench the deepest point of the crust under the pacific ocean, but it wasnt possible to stay long due to thee enormous oceanic pressure nearly crushing Bathyscaphe Trieste in 1960. It remains a mystery what is underneath the surface of the Mariana Trench, most are all hypothetical..... So it is out of question to attempt to explore via sea route, which leaves the land route. So digging deep enough into the deepest point of the crust has there ever been any recorded visit/attempt of visiting the Earth's mantle? We have sent space pobes to Mars, Venus, so it should not be difficult to explore deeper into our own planet, even build a suitable vehicle (most likely non manned robotic) that may visit the core ?