It's not every day that what is essentially nothingness would be major news, but today is that day: Scientists announced in Nature that after two years of study, they've identified a roughly 100-foot-long void in Egypt's Great Pyramid of Giza—built around 2500 BC, it's the most ancient of the seven wonders of the ancient world, notes the Guardian. It's the first discovery of a new structure in the monument since the 19th century, and it came by using muography, which can pick up on changes in density within rock. What was found, the BBC reports, isn't being called a "chamber," and it explains why: Also known as Khufu's Pyramid, the structure contains voids that are believed to have been incorporated to bolster the structural integrity of the pyramid.
While three muon technologies confirmed its existence, "we don't know whether this big void is horizontal or inclined ... [or] made by one structure or several successive structures," says Mehdi Tayoubi. It sits above the pyramid's "most striking" chamber, the Grand Gallery, a corridor that links the Queen's and King's chambers. An archaeologist who reviewed the work says it's possible the void was intended to "protect the very narrow roof" of the gallery, though others contend that for the cavity to effectively have that function, it would need to be smaller. The Guardian notes the pharaoh Khufu's mummy is missing, but a Harvard Egyptologist tells NPR the idea that the cavity is "a hidden room and the king's body is inside ... none of that is responsible speculation at the moment." The team next hopes to get approval to drill a 1.2-inch hole that a robot could fit into. (The world's largest pyramid was mistaken as a mountain.)