Somehow, while the rest of the ancient Egyptian world has crumbled around it, the Great Pyramid of Khufu at Giza remains standing, even after 4,600 years. Even through major earthquakes and the gradual loss of its gleaming white casing stones , the main structure of the pyramid endures, its granite and limestone blocks still firmly in place, almost as though the vast edifice were only just emerging from the throes of construction rather than slowly decaying. Archaeologists are still trying to