@RichBarna: Saying it took longer than we think is very different from saying an entirely different society built them. Maybe it did take a while... I don't know about that. But there isn't any evidence of a different society. If it existed, there would be evidence.

@simons-photography: Why don't you start a thread about extra-terrestrials? I'm curious to see what evidence you have for them, but if we post it all here it will get off-topic.