A Japanese high tech technolody called muon photography can detect cavities inside solid rock. Used on the great pyramid it was able to detect another enormous previously undiscovered great gallery above the great gallery we have all seen.

From our perspective a muon decays in a couple of milliseconds but due to a relativistic effect from moving at the speed of light it can travel many hundreds of km before it goes poof. A gamma ray hits our atmosphere and with a collision, gives birth to muons as well as a host of other sub atomic particles. The Japanese found a way of placing detector plates similar to X ray film and render a picture with super computers. It takes months to expose the 'film' and more time to render. Egypt's antiquites director Zwass is not thrilled with this technology.