1. The deepest mine in the world is the TauTona in South Africa and it is a megor 3.6 kilometers deep.
2. The distance to the mantle is about 35 kilometers deep.
3. I would see alot of magma and iron. It would be really bright also due to the fact that it is really hot down there in the mantle-the inner core. It would be really cool though to actually see if the inner core is actually solid or a liquid.