One of the most ancient prehistoric monuments in Italy is found in Sardinia beside the road from Sassari to Porto Torres. Situated in a large area of flat land, the impressive Mount d'Accoddi dominates the countryside. From close up, it looks like an ancient Sumerian ziggurat, a staired pyramid rising up high, from which the Sumerians and later the Assyrians and Babylonians scrutinised the heavens and offered sacrifices to the gods.
Worn away in the ground, an access ramp, supported on each side by a great wall of dry stones, leads thirty metres up to the top of the monument. Here there is a large rectangular promontory, 36x30m, about 9m higher than the surrounding countryside.

During this second operation an evidently important stone structure was discovered underneath the upper mound: a large room 15 x 2 m located 5½ m away in the surrounding countryside. This was probably a place for sacrifices, perhaps a temple. This archaeological research has led to the hypothesis of the original shape of the monument. Accordingly, there was a t pyramid with a small temple above. The construction seems to have been built between 4000 and 5000BC, while the nearby altar and menhir more likely go back to 3000BC.

All of this archaeological data has demonstrated clearly that Mt Accoddi is one of the most ancient monuments in Italy, of great importance for the prehistoric inhabitants of Sardinia; it was a pilgrimage site, where the various peoples of the island gathered to celebrate community rites and worship their gods. From the planimeter carried out it seems that the orientation of the monument was to the south (north-south direction), as if the access ramp had been devised to carry the celebrants in the opposite direction, north, to the summit, where the solemn rites were probably celebrated. This hypothesis roused the interest of E. Proverbio and G. Romano who, in 1986 began a series of archeo-astronomical studies to establish definitively the orientation of the main monument, as well as all the other parts of the complex .

The first measurement was taken with the aim of verifying the direction of the access ramp. Contrary to what the planimeters had indicated, the ramp exhibited a deviation of 6.3º eastwards when at the northern, nor was it rectilinear; rather, it is formed, they claim, from various segments with slight deviations among them. The sides of the central part of the monument, i.e. the large rectangle on the wall of dry stones, demonstrate orientations probably related to the points from which the moon shone during the important periods of its 18.6 year cycle. The measurements taken previously to develop the planimeters are thus shown to have been taken carelessly and imprecisely.

In the structure discovered by Tine inside the mound, the longer wall is east-west oriented; this leads us to think that already in these remote times, precise methods were known to work out the direction of the south and, therefore, also the equinox. The directional surveys carried out have allowed us, moreover, to establish that the lines which unite the more distant menhirs with the central monument and the other menhirs with the stone altar, are directed towards the point from where the moon appears when it begins to decline. Unless an amazing coincidence, this would seem to mean that for the people who built Mt Accoddi, the moon was a heavenly body of particular importance. It is increasingly obvious, however, that everywhere, in prehistoric times, the moon was the first celestial object that men elevated to the rank of heavenly divinity.