A new scanning technique has revealed what scientists believe is an empty space within the Great Pyramid at Gizeh . While it might be an architectural feature intended to limit the load upon the hallway beneath it, it could be a huge room. They also detected a smaller void at a different spot in the pyramid. “We don’t know whether this big void is horizontal or inclined; we don’t know if this void is made by one structure or several successive structures,” explained Mehdi Tayoubi from the HIP Institute, Paris. “What we are sure about is that this big void is there; that it is impressive; and that it was not expected as far as I know by any sort of theory.” … Much of the uncertainty comes down to the rather imprecise data gained from muography. This non-invasive technique has been developed over the past 50 years to probe the interiors of phenomena as diverse as volcanoes and glaciers. It has even been used to investigate the failed nuclear reactors at Fukushima.