Hollow Earth

As a child one of the first memories of school was seeing the world globe on the teachers desk or somewhere in the classroom. This object was impressed on us as children that the globe represented the shape of the world and gave us relative position of the land where we lived in relation to the other lands of the earth. A lot of blue was on the globe with the word sea and or ocean describing the area of blue. We were told this was water. At the center of the earth is a core consisting of molten rock at extremely high temperatures and between the core and the surface are other layers of rock until we get to the surface area upon which we live. We know there are caves about ground and underwater, cavernous places that lead into the earth. How far down do they go? The further down we as human being have gone is approximately eight miles and the distance we are told is at least "twelve thousand miles" to the center. That is a lot of space for anything, isn't it? Let us explore through l available resources what has been found about this old world of ours, shall we????