Step Pyramid of Djoser, Saqqara — designed by the polymath Imhotep around 2650 BC, this is where it all started. The oldest substantial stone structure on earth, built a full century before the Great Pyramid. Imhotep was later deified by the Egyptians and identified by the Greeks with Asclepius. Not bad for an architect.
© Dennis G. Jarvis, CC BY-SA 2.0, via Wikimedia Commons