In time, the Ancient Egyptians stop constructing pyramids for burial sites. Why? The huge size of the pyramids often acted as a humongous sign to grave robbers that treasures could be found there. The tombs were moved to cliffs like those in the Valley of the Kings. The pyramids were also too expensive and took too long to build, so they were decommissioned.
In 332B.C., Egypt fell to Alexander the Great.