However, scientists do not all agree on this. John West and Robert Schoch have discovered water erosion on the Sphinx. But, in the middle of the Egyptian desert, where could the water have come from? Heavy rain was only common in Egypt around 5000 BC. So West and Schoch believe that Khafre can't have built the Sphinx. The Sphinx must already have existed at Giza when the pyramids were built. But we have no idea who might have built it.