How could this happen?

0005 How could this happen? This question has been bothering me for some time now. I shall try to convey what I mean, and where I am using this question. Let me begin with an example. So we have the Pyramids of Giza, people have so many theories about how these structures are made, why were they made, what is there astronomical importance, etc. What I do not understand is how can it be possible that there was such a vast gap in centuries and generations, that there are no witnesses who could have documented the creation of these amazing structures? Who could have passed it down through generations? So does that mean entire bloodlines have been wiped out from the time when the Pyramids were built till this day? It appears to be. But how could this happen? Why is there a sudden and long gap in generations? I believe battles, wars, plagues and lack of historians may be the reason, we lack absolute pieces of evidence. Throughout centuries mankind has evolved in standards of living by studying, discovering, inventing, designing, in every field of work we have known today. The man has always argued with facts and logic to reveal certain answers and make our lives much more simple, elegant and fast. Yet to me it seems the concept and importance of documentation came quite late and even though when it came, probably it was one of those things man was not concerned about updating or maintaining it. Or is it possible that man did preserve it, but we are yet not able to find it? But how does a man know, which moments are to be documented and which are not? I mean the people who built the pyramid might have expected that there are more to come. Did they know that what they made is of great significance to the coming new generation? If yes, then why didn’t they clearly mention the schematics, the design, and the architecture? They had hieroglyphics to communicate, isn’t it? I know I have been asking too many questions now. Well, this is what always bothers me when I am trapped in our timeline trying to figure out theirs. What do you think?