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.