Answer:
1. Considering the massive size of the structures, it is improbable to think that man is actually capable of building them.
2. And the intelligence and calculations needed for this construction is beyond the capacity of man, considering the age and times of the ancient Egyptians.
Explanation:
While Egyptologists and historians have, through years and years of research, have found evidence that it was actually the Egyptians that built them, there are also some people who held the belief that they are actually made and constructed by aliens. The humans of the ancient time that these structures were constructed were incapable of having the intelligent power and manpower and strength to carry out these works, with big blocks of stones and massive heavy structures to be made. However, the article "Who Built The Pyramids" shows the findings of Egyptologists Mark Lehner and Zahi Hawass who has worked to uncover the truth about these massive buildings of ancient years, trying to prove who actually built and how. They argued that, with all the workforce needed to actually bring about the construction of these structures, it is evident that the people of Egypt indeed were the workers and builders of these structures, and that too not as slaves (unlike many claims) but more as a sense of obligation to the king. And to refute the alien builder theory, there are definite proof that shows that it is humans and not aliens who built it. There are settlements that housed the workers, bone remains that have been examined by scientists and doctors, who have proved that humans and not aliens are the workers. Added to it, there seem to be no findings or even a shred of evidence too prove aliens have indeed been there, let alone construct that. Considering the massive structure of the pyramids, it is probable to think that man is incapable of constructing something like these, but like Lehner and Hawass has pointed out, there are lots of evidences to prove man actually built them. But there are still other group of theorists and believers that thinks aliens and not humans built them.
