The Great Sphinx sits on the west bank of the Nile, just to the southeast of the pyramids at Giza. While the Sphinx is considered the oldest monumental sculpture in Egypt, its exact date of construction is unknown. Modern Egyptology dates the Sphinx to the Old Kingdom, during the reign of the Pharaoh Khafre (c. 2558–2532 BCE). The head of the Great Sphinx is believed to portray Khafre (also Khefren or Chephren), the builder of the second largest pyramid of Giza. The Sphinx is carved into the limestone bedrock of the Giza plateau, which also served as the quarry for the pyramids and other monuments in the area. The body appears uneven because wind and sand erosion have damaged the softer layers the native limestone between the base and the head. Even during ancient times the Sphinx had begun to weather as it was buried to shoulder height in the desert sands. The first documented attempt at clearing the site was about 1400 BCE, during the reign of Thutmose IV (1401–1391 BCE), when workers managed to dig out the front paws. Sporadic efforts at excavating continued over the millennia until the entire Sphinx was finally cleared between 1925 and 1936. Attempts (not all successful or appropriate) have been made to repair and stabilize the stone base and rock cut body. Some sections have been restored with blocks of stone. For an interesting discussion of the varying theories of the origins and dating of the Sphinx, check out The Great Sphinx of Giza.