Since the Pharaoh was identified with a living god, assuring his afterlife was fundamental for the consistency of religion and therefore of power. As a consequence, great efforts were put by the state into the construction of the pyramids. It is important to say that there is no mystery in these buildings: Egyptians could build the pyramids because of the wealth of the state. Dozens of royal pyramids were constructed in Egypt; their builders were not slaves or peasants, but specialized workers. The first is the so-called step pyramid of king Djoser in Saqqara, but the first masterpieces are the pyramids built by Snefru at Dahshur. The so-called Bent Pyramid and the Red Pyramid. After Snefru came the builders of the world-famous pyramids of Giza, a desert plateau to the west of modern Cairo. The Great Pyramid, built by Snefru's son Khufu. The Pyramid of Khafra and finally, the Menkaura Pyramid. The Great Pyramid of Khufu is the greatest ever built. In this pyramid, all the ideas on the sky afterlife of the Pharaohs were put in action, so it is impossible to understand it without Archaeoastronomy. The pyramid is enormous: 230 metres side base, about 146 metres high; the slope is 14/11. Slopes were measured in terms of rational tangents, that is, using right triangles with integer legs. The pyramid consists of more than 200 horizontal courses of limestone blocks and was cased with white limestone, today almost lost. The original entrance (today visitors enter from a looters' passage) is on the north face, and gives access to a descending passageway and an unfinished room. However, an ascending corridor branches off and comes out in the so-called Grand Gallery, a huge room 46 metres long and more than 8 metres high. From here one can go in the so-called Queen’s Chamber: the Serdab, with the niche for the statue; or, one can ascend more, up to the King’s Chamber. Inside there is Khufu’s granite sarcophagus. In both the upper chambers there are two little rectangular openings, on the north and south walls respectively. They lead to shafts which cross the monument diagonally. Those of the Queen’s Chamber end inside the monument, those of the King's chamber exit the pyramid through the north and south faces respectively. The exits are almost at the same height, about 80 metres. There can be no doubt that the construction of these structural elements was very complex, continuing over many years. Inclinations of the shafts were carefully maintained, but why? They have sometimes been interpreted as ventilation channels, but of course this has no sense: after construction there was no need of ventilation, during construction a single vertical channel would have been much better and simpler. The answer derives from the profound connection between the pyramid and the stars. Yes, there was an intimate connection between pyramids and stars – this should come as no surprise, as the pyramids are the tombs of the Pharaohs, and the Pharaohs were destined to ascend to the sky. Be careful, however, as a lot of pseudo-archaeology exists on this subject. The fact that the shafts start from the north and the south sides of the chambers, combined with the fact that the sides of the pyramid are oriented cardinally with extreme precision means that they are directed to specific points along the celestial meridian. If we compare the data with the sky, we could find that around 2 500 BC the northern shafts pointed to Thuban, the pole star, and to Kochab, a brilliant star of Ursa Minor, respectively. The southern shafts pointed to the Orion's belt - the three stars Al Nitak, Al Nilam and Mintaka - and to Sirius. So we have here a list of stars belonging to exactly those regions of the sky – the circumpolar stars and the stars of Orion-Sirius – which are described in the Pyarmid Texts: four out of four channels of the Great Pyramid pointed, at the period of construction, to the upper culmination of four stars which play a key role in the Egyptian religion. It is important to stress that the shafts are a purely symbolic architectural feature, as they are not perfectly straight. Moreover, only the upper shafts reach the surface of the pyramid, while the lower shafts end in two small doors. To conclude then, there can be no doubt: the function of the channels was to direct symbolically the Pharaoh to his proper destinations in the sky.
