Short answers, pulled from the story.
The earliest known Egyptian pyramids stand at Saqqara west of Memphis. Step-pyramid-like structures like Mastaba 3808 attributed to pharaoh Anedjib may predate the Pyramid of Djoser built during the Third Dynasty.
Egyptologists attribute the first historically documented Egyptian pyramid to the 3rd Dynasty pharaoh Djoser. Although Egyptologists often credit his vizier Imhotep as its architect, the dynastic Egyptians themselves did not credit him with either designing Djoser's pyramid or the invention of stone architecture.
Recent archeological research suggests Fourth Dynasty pyramid construction was heavily dependent on Nile-based transport. Sediment cores show evidence of a Nile-connected harbor functioning along the Giza plateau during Khufu's reign that helped large scale movement of limestone blocks and other materials.
All Egyptian pyramids were built on the west bank of the Nile which as the site of the setting sun was associated with the realm of the dead in Egyptian mythology. The shape of a pyramid is also thought to be representative of the descending rays of the sun and most pyramids were faced with polished highly reflective white limestone.
A burst of pyramid-building occurred in what is present-day Sudan after much of Egypt came under the rule of the Kingdom of Kush which was then based at Napata. Napatan rule known as the 25th Dynasty lasted from 750 BCE to 664 BCE and the Meroitic period experienced a full-blown pyramid-building revival between 300 BCE and 300 CE.