The Hollow Earth

i do 100 % believe that the earth could be is hollow. In a sense, i guarantee you it's hollow,. There are huge cave systems that are so complex that they all haven't been explored. Could bigfoot live there? Dog men? These cryptits, these creatures, what are they? Why do they come from the inner earth? Is it a portal that goes to their realm? I don't know. But for me, yes, i believe the earth is definitely hollow.