This series is great for entertainment purposes, yet anyone who jumps to the conclusion that it must be aliens if something isn't understood should awaken one's inner sceptic. This makes them no different then the people that assume that if something isn't explainable then some divine being must be responsible. Not trying to encourage atheism, but skeptisism as they claim this is a theory, but yet I see no scientific fact. But I do like all the stories behind it, they do teach some facinating things about various cultures, I just take it at face value. This is entertainment, not a science.