The little-known cavity may support the theory that the 4,500-year-old monument to Pharaoh Khufu was constructed inside out, via a spiraling, inclined interior tunnel—an idea that contradicts the prevailing wisdom that the monuments were built using an external ramp.
The inside-out theory’s key proponent, French architect Jean-Pierre Houdin, says for centuries Egyptologists have ignored evidence staring them in the face.
Video Clip From Unlocking the Great Pyramid Documentary
[Source: National Geographic]