The strange Egyptian disc often called the Sabu Disk is one of those ancient objects that looks almost too modern to belong to the world it came from. Found in 1936 inside the tomb of Sabu, a high-ranking official from Egypt’s First Dynasty, the object dates to around 3100–2900 B.C. and is now housed in the Egyptian Museum in Cairo. Its shape — a shallow stone vessel with three curved lobes around a central opening — has made people compare it to a propeller, a steering wheel, or even a mechanical component.

But the real mystery is not that ancient Egyptians made something strange. It is that the object’s design feels difficult to explain with certainty. Some theories suggest it may have been a ritual bowl, an offering vessel, a symbolic object, or even a functional device. Yet its fragile material and unusual structure keep raising new questions. Here are 10 clues that explain why the 5,000-year-old Egyptian disc continues to fascinate archaeologists, engineers, and mystery lovers.