I have no doubt at all that people other than Europeans visited the Americas prior to...what? After all, folks came here during the last Ice Age from somewhere. I see no objection to the theories that there was a land bridge from Asia, or that some crossed by land and water from Northern Europe. It is also obvious from recent archeological discoveries in South America that there was coastal "boating." As for our ancestors' abilities, the islands of Polynesia weren't settled by land bridges!

But to say, "The Chinese did this" or "Space aliens helped with that" -- well, I take a skeptic's "show me" attitude.

Did the poles shift in the past? Certainly. Will they shift again? Most likely. Can I or anyone else do anything about it? No. If mankind becomes extinct, will the planet go on? Yes. Ergo, I can't be worried about polar shift, the Mayan calendar, the Yellowstone caldera, asteroid hits, and things like those. I'll worry about things I can do something about.