There is an academic ‘mainstream’ that establishes which things are right (according to science) and which are not. Within his creations are theories that help us to understand reality, and in contemporaneity, this corpus of knowledge remains virtually unquestioned, except within the same scientific field where stipulated how to proceed to develop a new theory.(The Hollow Earth Theory)
Theory of the Inner Earth(The Hollow Earth Theory)
However, this was not always the case. Throughout the eighteenth and nineteenth centuries, at the dawn of modern science, verification mechanisms were not institutionalized and alternate theories abounded. Many claims that this was the golden age of science before the great powers seized it and imposed their notions of what is true, either to conceal things or simply to maintain their control over the world.
One of these alternate theories (which actually drinks from the medieval Christian tradition) is the Hollow Earth theory. According to it, the earth is constituted by an outer region and an “inner surface” which can sustain life and could be the cradle of ancestral civilizations that would have made contact with humanity in ancient times. A less radical variant of the theory states that while the earth is not entirely hollow, there are regions of caves and large holes between the mantle and the crust, which sustain life with water seeping from the surface and heat from the Center of the Earth. Likewise, the most radical version includes a sun located in the center of the earth, which illuminates these unknown regions.
In both cases, unknown ecosystems, extinct species, and even advanced civilizations could live in the central region of the earth, isolated from humanity. Systems of tunnels and caves would communicate with these regions, but the main entrance would be two huge holes located in each of the terrestrial poles.
Theory tests(The Hollow Earth Theory)
Proponents of this theory claim that the depth of the earth is virtually unexplored: the deepest hole excavated by mankind barely exceeds 12 kilometers, while the earth is more than 6,000 kilometers deep. They also stipulate that magnetic measurements do not exactly coincide with current theories, so there must necessarily be empty spaces in the middle of the earth.
There have been several expeditions in search of these tickets located at the poles, the last planned for the year 2006 and that was canceled due to the death of its organizer (Steve Curry) by a brain cancer, something that has given rise to accuse the Great powers of trying to hide what is there. Likewise, proponents of hollow earth theory argue that there is no other way to explain the interest of governments in controlling Arctic and Antarctica and the apparent misinformation about these places.
Unfortunately, there is not much information about characters who have visited these territories. Many expeditions were planned in the 19th century, but none were made due to logistical problems or lack of funds. The most well-known figure to have come to the hollow land is Karl Unger, who piloted a submarine during World War II on an expedition to the South Pole and entered through an underwater tunnel.
The truth is that many characters, including Hitler, were convinced of the existence of an underground civilization. Hitler even sent several expeditions, and some claim that he escaped from Germany after the Soviet invasion and is hidden somewhere in the underworld. In any case, the possibility of life (intelligent or not) under the earthly mantle continues to fascinate humanity.