You can get involved and help support us through our Patreon. Check out all the various tiers and rewards at http://www.patreon.com/aliensexplored before picking the right one for you!

Mythology, folklore and legend, from countless civiliations put forward a concept that there is a land below the surface of the Earth. Scientists across the centuries have also speculated as to the possibility. Most recently, theories have surfaced that such spaces are bases for UFOs. But is there any substance to this subterranean secret?