Researchers studying the Great Pyramid of Giza, built in around 2560BC as a tomb for the Egyptian pharaoh Khufu, believe they have discovered two previously-unknown cavities within the structure.

Scan Pyramids, a collaborative project involving a number of universities, companies and scientific institutes, has been using muography, thermography and 3D simulation to discover more about the pyramid.

Describing the muography technique to Discovery News earlier this year, researcher Mehdi Tayoubi said: "Just like X-rays pass through our bodies allowing us to visualise our skeleton, these elementary particles, weighing around 200 times more than electrons, can very easily pass through any structure, even large and thick rocks, such as mountains."