>> The Great Pyramid of Giza is the last of the Seven Wonders of the World still standing. And now, scientists have discovered a large and mysterious void at its heart. They found an internal structure at least 30 meters long, directly above a passage known as the Great Gallery.
Its got experts puzzling over what it is. The pyramid was constructed as a monumental tomb during the reign of Pharaoh Khufu more than 4,500 years ago. To peer into previously unexplored parts, researchers used an imaging technique called muon tomography, that involves tracking cosmic particles that bombarded our planet up close to the speed of light and it's penetrate deep into solid objects.
It's the first major in a structure found in the Great Pyramid since the 19th century. Now, scientists hope the non-invasive scanning technique will reveal more secrets of the ancient worlds.