Experts discover two 'cavities' in Egypt's Great Pyramid
Egypt's Great Pyramid of Giza could contain two previously unknown 'cavities', said scientists studying the millennia-old monument. Using radiography and 3D reconstruction, the scientists were able to point out two "voids" in the pyramid, one behind its northern face and another behind its north-eastern flank. The pyramid was built 4,500 years ago under ancient Egyptian Pharaoh Khufu.