I Wanna Know What Is Your Theory As to Who Built the Pyramids

My theory (not my own but one I believe in) is that they were built by an advanced civilisation around 30000 years ago. A civilisation wiped out by a catastrophic earth disaster some 13000 years ago. The pyramids were designed to capture and harvest sunlight (my theory) for power using technology we have not yet rediscovered.

The stones used were selected to withstand the elements and internal temperatures generated.

The eygptian tombs we visit today were parts of the surviving and hijacked pyramids by a much later civilisation from around 2000 years ago.