Hollow Earth Theory

I found it very interesting that this concept has survived from ancient times. It started out in Greek and Celtic mythology; where they believed that caverns on the surface of Earth could lead you deep within the Earth to a Hell or afterlife. These stories continued to grow when medieval knights and saints were said to have entered an ancient cave that led to purgatory. In the centuries to follow it was speculated that perhaps other civilizations actually lived within the Earth. In 1781, Milfort with several Creek Indians went into a cave system by the Red River in Mississipi; where he made claims that these systems could easily hold 20,000+ families. Many different versions exist, some believe a miniature sun exists within the Earth with many different species.  Others believe there is no sun, but the species still exist. These species were said to have been discovered in the Caucasus Mountains. Maps have been created that show entry points and what the inside looks like; plenty believe UFOs have entered in through the north and south poles to visit the civilizations.

This theory at a time tried to explain for gravity, the aurora borealis, and tectonic plate movements. This theory also seems to have started as more of a religious one that throughout the centuries morphed into a Sci-Fi adventure as some claim to have traveled into the Earth. They point to different photos like Essa7 and first hand accounts to give their theory credit. It's a pretty cool idea from a Sci-Fi perspective, as subterranean fiction helped move this idea back into view.

http://www.new-age-of-aquarius.com/hollow-earth.html