I'm not the one assuming anything. I know construction of those things often took about a life time or two.
You know nothing. Obviously. These civilization are completely absent of history books and we officially know nothing about them beside the massive blocks remaining.
While history is one of my least studied subjects I know that they do not hide knowledge of ancient civilizations. They just admit to not knowing much about them.
Right, but they aren't digging neither. The only ones who do are independent researchers.
