As noted elsewhere the Pyramids were not built by slaves, they were built by the best craftsmen in the kingdom. Second thing to note is the Great Pyramids didn

As noted elsewhere the Pyramids were not built by slaves, they were built by the best craftsmen in the kingdom. Second thing to note is the Great Pyramids didn't spring up from nowhere. The Egyptians spent hundreds of years building bigger and bigger Pyramids, refining the techniques. Long enough they were able to look at the older ones to see how they weathered as well as having written records of the many mistakes along the way.