Hollow Earth doesn’t exist, everyone knows that. And yet it DOES! Some theorize that it isn’t just a singular location so much as a type of location which exist within the border, where the walls between the material world and deep supernatural connect. If that is the case, then ‘Hollow Earth’ is simply the underground portion of the Border. Those who have ventured into these tunnels talk both of cavemen and dinosaurs as much as they talk of serpent-men and degenerated mutants.