Top 10 Mysteries of Ancient or Lost Civilizations - YouTube
I belief my explanation solve the mystery of how pyramid is built.
All other theories base on common sense so it can be mislead by each other.
My explanation is : The pyramids is built by "sculpting".
The history of pyramid can longer than all we belief.
Why pyramid? It is only place safe for a land animal survive. So did their King.
Instinct of land animals escape from this natural disaster is obvious noticed by researchers or legend told by old observation in historical document.
And my proposition is the pyramid is built from top to the bottom. This reverse most people's imagination.
So I belief you can tell what natural disaster help Egyptian built the pyramid.
Some evidence: in this video, Water erosion in the bottom of the pyramid.