The hollow Earth theory.

I've been doing some research about the hollow Earth theory.
I started to get into it when I read Gordon William's Free fall and Closer book's, It got me interested on the topic, it fascinates how there can be a world under are feet, and we don't even know if it's true or not, or maybe it is true and where not suppose to know about it.
There are people that know about this stuff that say they think that there's are entrances to the hollow Earth at the north and south poll, and other smaller entrances on other parts of the the Earth surface.
Their is so much to know about this topic that it's hard not to think that there's more to are planet then what we know already.
So what I wan't to know is who came up with hollow Earth theory, and why would they, like Jules Verne's Journey to the center of the Earth, how did he come up with that story, and other story's that talk about the topic, what gave them all the idea to come up with this theory? all I can say is, all ideas come from something that is real.

Errrm ok. Please keep in mind that this isn't a forum made for the Tunnels book series. You can talk about Tunnels though. Just saying.

Ok