They were not built as described in modern textbooks. You have to be a fool to believe that.

My personal opinion, which is based on others science and investigation is that they were built either by a different civilization, or the knowledge was passed down to the Egyptians on how to build them.

This civilization, suffered a great catastrophe around 12500bc. The same date Plato attributes to Atlantis. A great flood roared the earth, wiping out most of human civilization to that date. There are numerous accounts of this flood in many different cultures with no connection to eachother.

Many sights have been found lately to support this. There is also a widespread theory that suggest that a large meteor hit earth at same time, 12500bc. This is a very TLDR 😉 I recomend you search up Graham Hancock and Randal Carlsen on youtube if you are intrigued ☺️