Well, that is my experience, too. I'm very open so I examined several so-called proofs of alternative history. Unfortunately, in all cases they can be explained

Well, that is my experience, too. I'm very open so I examined several so-called proofs of alternative history. Unfortunately, in all cases they can be explained in more traditional ways, or were a fabrication like the crystal skulls. This doesn't mean that we haven't been visited by alien civilizations, but as far as I can tell we don't really have any definitive proof. Unless we equate aliens with gods - but even then the only artifacts we have are just scriptures.