"Energetic centres, power plants, if you like," Fleur explained with a grin. "Water fed, and controlled, in to subterranean chambers creates a compression wave that generates electrons, magnified by the granite in the Kings Chamber to a certain frequency. This creates intense electro-magnetic energy. What was this used for, who knows? Was it to send messages into space? Was it a time-travel device? Was it to travel between dimensions? We may never know."