Comment on Visible Structures by steve-burg
When I was in college, I wrote a short story about astronauts discovering that the moon was an immense spaceship. Covered in a thick layer of dust and rock, but underneath that it was a metal structure. It would certainly be a startling discovery! 
this very idea is visited in the anime gurren lagann, in a surprisingly novel way too. i guess its natural for people to ascribe these ideas to the things around us. heaven above us... hades below, and all the varying narratives about the moon. so cool really.