We don't know crap. The most intelligent scientists of their time thought the Sun orbited the earth, the world was flat
and Columbus was first to discover America.
We are arrogant, we assume we know all. Hint: we are far from knowing about a lot of things.
As a whole....we've got a lot to learn.
At the time things did happen, we weren't there and have no conclusive proof on how the Pyramids were built,
Stonehenge etc. Get a grip and come back to earth. A lot we say we know is based on theory, no tangible proof.
Keep an open mind and deal with facts alone. We'll learn more.