The great Egyptian Pyramids of Giza have inspired awe and wonder and, quite likely, fierce speculation from the moment they were built. In fact, even the date of their construction has become a topic of debate. Explorer, survival expert, and host Josh Bernstein takes a hard look at the competing theories as to who really built the pyramids--and when. Archaeologists say it was the ancient Egyptians, others argue for an even older civilization. Josh examines the evidence, explores secret chambers in the heart of the Great Pyramid of Khufu, visits the first pyramid ever built, and tries his hand at ancient stone-quarrying techniques. It's a hard-won perspective, but, with the discovery of a mysterious flooded chamber deep beneath the Sphinx, Josh learns what appears to be the final truth.