Limestone doesn't just erode on the surface. It dissolves from below. When you have massive water flow over a limestone bedrock like the Giza Plateau, that water penetrates downward, carving out voids, caves, and extensive underground networks. This is standard karst geology, visible in limestone terrains all over the world. So the question becomes: what lies beneath Giza? Author and researcher Andrew Collins explored this idea in his 2009 book, Beneath the Pyramids, where he documented actual cave systems below the plateau. If the region experienced catastrophic flooding during the Younger Dryas or earlier meltwater events, those flows wouldn't have just scoured the surface. They would have honeycombed the subsurface with chambers and passages, some of which may still be undiscovered.