Pyramid of Meidum

29.3886°N, 31.1572°E.

Transitional pyramid at Meidum, attributed to Sneferu (~2600 BCE), originally the tallest building on Earth at 92 metres before its outer casing collapsed catastrophically — possibly during construction or possibly in antiquity. The structure now stands 65 metres tall as a stepped tower core surrounded by a ring of debris. The collapse exposed the pyramid's accretion-layer construction, an inwardly inclined technique that proved unstable when extended to a smooth-sided form. The collapse rubble contains intact wooden scaffolding, suggesting workers fled mid-repair and never returned. Sneferu went on to build the Bent Pyramid and the Red Pyramid at Dahshur, evolving the design until the geometry held. Meidum is the engineering disaster Egyptian builders learned from.

The pharaoh who built three pyramids built them in a sequence of failures — and we can read the lesson in the rubble.