Favorite Answer

There is no evidence that aliens built the Egyptian pyramids that is not better in quality or quantity than evidence that the Egyptians built them all by themselves.

Get that?

Evidence that aliens did it = small, not good, mostly (if not all) theoretical

Evidence that people did it = lots of it, high quality, empirical

Now this isn't to say that a big, shiny UFO might not be dug up from under a pyramid someday, but that hasn't happened yet. It may not ever happen.

And it wasn't human beings who built pyramids, it was a society of humans that did it. We've got plans, we've got ancient blueprints, we've got hundreds and hundreds of housing projects near the pyramids where the workers lived. We've got lines of increasingly impressive pyramids being built over a long period of time. The really great pyramids at Giza weren't a first attempt. They were the pinnacle of a long history of Egyptian pyramid building.

Anyway, what makes you an expert on what humans could have accomplished 5000 years ago? Me? I'm an archaeologist.