Did a highly advanced civilization exist in prehistory Is the Giza Pyramid a remnant of their technology Then, what was the power source that fueled 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 acoustical device By its size and dimensions, this crystal edifice created a harmonic resonance with the Earth and converted Earth's vibrational energies to microwave radiation. The author shows how the pyramid's numerous chambers and passageways were positioned with the deliberate precision to maximize its acoustical qualities. This may be the same technology discovered by Nikola Tesla and the solution to our own clean energy needs.