Did a highly advanced civilization exist in prehistory? Is the Giza Pyramid a remnant of their technology? Then, what was the power source that fuelled such a civilization? The technology of harmonic resonance, claims renowned master craftsman and engineer Christopher Dunn. In a brilliant piece of reverse engineering based on twenty years of research, Dunn reveals that the Great Pyramid of Giza was actually a large acoustal device! The author shows how this may be the same technology discovered by Nikola Tesla and the solution to our own clean energy needs. Egyptology should never be the same. But probably, once again, this theory, unfortunately, will be 'brushed under the carpet' by historians who refuse to think 'outside the box' and re-write the history books.