where is the chocolate factory?

Being a little patriotic, I feel obliged to say Belgian chocolate is the best in the world. I don't really know the answer to your other questions, but I suggest you look it up on wikipedia or another site like that. (that's what I do when I have questions like yours :) ) Also, I believe the most expensive chocolate is the american Noka chocolate, but as they apparently actually only melt imported French chocolate, give it another shape and put it in boxes, the only reason I can give for their expensiveness is greed for money.

As far as I'm concerned one of the finest chocolate that you can find is in Switzerland. Then, every country might have great chocolate producers.

Hershey, Pennsylvania is where the Hershey Chocolate Factory is located and you can go there and take a tour. I am planning a trip there because for me that is actually "heaven on earth." I hope I will see some of you on the tour. hehehe