The Great Pyramid in Egypt built about two thousand years BC is not just a pile of stones. It is a grave containing a burial chamber, passages, and ventilation ducts, etc. It is an engineering feat. It took many centuries of experimentation till it was possible to build a true pyramid. There are about one hundred pyramids in Egypt. After about 500 years when the Egyptians stopped building pyramids, the Nubans who occupied Egypt around 1000 BC, built in Meroe another two hundred pyramids but far much smaller than those at Memphis.