Egypt's Most Brilliant Pyramid Portcullis

Video Description

A portcullis in the pyramid context is a heavy stone slab that drops to block a passage. It’s famous in medieval castles as a metal spiked door, but some of the earliest examples are in Egypt’s pyramids. Most pyramid portcullises are vertical granite slabs in grooves, often set close together in series—effective on paper, but vulnerable in practice: lift with a lever, jam with wood, repeat. Today I’m covering what I believe is Egypt’s most ingenious portcullis design: the Bent Pyramid’s diagonal-closing system at Dahshur. To explain it, I built a simplified model so we can “see through” the walls. In the Bent Pyramid’s upper passage, the two granite slabs are paced far apart. The western slab is down; the eastern slab is still raised and propped. The design intent is clear: these slabs were meant to slide diagonally down prepared stone faces into sockets, not to be operated repeatedly like a working door. Once lowered, raising them again would be extremely difficult. Here’s the genius part: a robber approaching the closed slab would first assume it’s a normal vertical portcullis. But when you pry upward, the slab doesn’t rise cleanly,—it tends to tip and bind against the angled surfaces. Even if the attacker learns it’s pointed and diagonal, the geometry defeats the standard “lift-and-prop” method: the opening gap becomes an acute triangle, so props tend to slip out rather than hold. Add the tight corridor walls—your crowbar hits stone before you get meaningful leverage. So the Bent Pyramid portcullis attacks the robber’s toolset in three ways: it disguises its motion, it converts upward force into sideways binding, and it creates a gap that’s hard to wedge and hold. And that may help explain why the eastern slab shows no obvious damage consistent with repeated prying attempts. References: Creighton, S. (2012, November 13). Re-evaluating the portcullis security system of the ante-chamber within the Great Pyramid Edgar, J., & Edgar, M. (1910). The Great Pyramid passages and chambers (Vol. 1). Bone & Hulley. ([Google Books]) Fakhry, A. (1959). The monuments of Sneferu at Dahshur, Vol. I: The Bent Pyramid. General Organization for Government Printing Offices. ([MERETSEGER BOOKS FZ LLC]) Hamilton, K. (2023, October). The Bent Pyramid revisited: A layman’s guide (DOI: 10.13140/RG.2.2.33698.20168). ResearchGate ISIDA Project. (2013). Dashur. Bent Pyramid. [https://isida-project.org/egypt_december_2013/bnt_pyramid_sat_en.html](https://isida-project.org/egypt_december_2013/bnt_pyramid_sat_en.html) ([ISIDA Project]) Maragioglio, V., & Rinaldi, C. A. (1964). L’architettura delle piramidi menfite. Parte III: Il complesso di Meydum, la piramide a doppia pendenza e la piramide settentrionale in pietra di Dahshur. Monnier, F. (2020). A new survey of the upper chambers of Snefru’s pyramids at Dahshur. The Journal of Ancient Egyptian Architecture, 4, 1–17. ([ResearchGate]) Monnier, F., & Puchkov, A. (2016). The construction phases of the Bent Pyramid at Dahshur: A reassessment. ENiM, 9, 15–36. ([Enim Egyptologie]) #AncientEgypt #PyramidEngineering #LostTechnology #AncientMysteries #Archaeology #MegalithicStructures #AncientMechanisms #mechanicalengineering #YouTubeHistory #EngineeringHistory #HiddenHistory #AncientWaterTech #OldKingdom #GreatPyramid #HistoryMysteries #AncientEngineering #EgyptianHistory #history #egyptology