In 1993, Heston teamed up with John Anthony West and Robert M. Schoch in an Emmy Award-winning NBC special, "The Mystery of the Sphinx". West and Schoch had proposed a much earlier date for the construction of the Great Sphinx than the one which is generally accepted. They had suggested that the main type of weathering evident on the Great Sphinx and surrounding enclosure walls could only have been caused by prolonged and extensive rainfall and that the whole structure was carved out of limestone bedrock by an ancient advanced culture (such as the Heavy Neolithic Qaraoun culture).