For 45 centuries, the Great Sphinx has cast its enigmatic gaze over Egypt's Giza Plateau. The biggest and oldest statue in a land of colossal ancient monuments, its scale is staggering: The mighty head towers as tall as the White House, while its body is nearly the length of a football field. This strange half-human, half-lion image has inspired countless fantastic theories about its origins. How was it built, and who or what does it represent? Surprisingly, the scribes of the period when it was built—during Egypt's Old Kingdom—passed over it in silence. Adding to the mystery, archeologists found that its creators abruptly discarded their tools and abandoned the Sphinx when it was nearly complete. Searching for clues, NOVA's expert team of archeologists, including Mark Lehner, director of Ancient Egypt Research Associates, carries out eye-opening experiments.