The Great Pyramid of Giza is one of the wonders of the world and is a magnificent feat of ancient architecture. But an Italian professor of archaeoastronomy thinks that it contains something that makes it even more amazing. He believes that the void at the center of the Great Pyramid houses a throne made from meteorites, the Daily Mail reports.

The void was discovered in November 2017 and is approximately 30 meters long. It’s located above the Grand Gallery, a long corridor situated between the King and Queen’s chamber. Since its discovery, researchers have been trying to figure out why it was used. Professor Giulio Magli, the director of the department of mathematics and professor of archaeoastronomy at the Politecnico di Milano, proposed his hypothesis after a deep dive into the Egyptians’ ancient religious texts.

The Pyramid Texts, which documents ancient Egyptian funerary rites and beliefs, state that the Pharaoh “will have to pass the ‘gates of the sky’ and sit on his ‘throne of iron’ before he ascends to the stars of the North.”

As the International Business Times reports, the pyramid contains four shafts that are directed towards the sky. Two of these shafts are enclosed by small doors. The door facing south has been examined but the north-facing one is still a mystery because it is sealed.

Magli thinks that these doors are the “gates to the sky” that the Pyramid Texts spoke of. He also believes that when opened, the north door could lead to the void and to the pyramid’s very own “Iron Throne.”

According to Ancient History Encyclopaedia, the Great Pyramid of Giza was built during the reign of King Khufu between 2589-2566 BCE. Magli says that based on what researchers know of his mother Queen Hetepheres’ throne, the pharaoh’s would be made of wood and covered by metal sheets. Based on the ancient texts, that metal is most likely iron that could have been harvested from meteorites.

This isn’t unheard of. Ancient Egyptian artifacts made from meteoritic iron have been found before. As IBT notes, King Tutankhamun’s dagger is made from this celestial material. Meteoritic iron has a high concentration of iron that distinguishes it from regular iron. The Ancient Egyptians would have been melting this metal down centuries before the Iron Age, which started around 1200 BC.