The Hall of Records is a legendary hidden chamber said to lie beneath the Great Sphinx, believed to contain lost knowledge from an advanced pre-dynastic civilisation. The concept was popularised by Edgar Cayce, who claimed the chamber held records of Atlantis and ancient technologies predating known Egyptian history. Seismic surveys and ground-penetrating radar conducted in the 1990s detected rectangular voids beneath the Sphinx enclosure, intensifying speculation despite excavation being prohibited. The site remains one of Egypt’s most contested mysteries, sitting at the crossroads of archaeology, ancient technology theory, and suppressed-history claims.