The necropolis of Anghelu Ruju is one of the most important archeological sites of Sardinia, because it has one of the most vast and ancient complex of artificial caves utilised by different civilisations from approx. 3000 to 1500 bC . Discovered by chance in 1903 and susequently explored in different phases up to 1967, the necropolis counts 38 domus de janas on a small hill in proximity of a small watercourse, the Rio Filibertu. The calcareous sandstone hill helped the creation of the tombs, excavated with rudimental rock picks, but the thickness of the rock, limited their regular development in height. The tombs are of two types:
- calatoia type (the most ancient) with irregular plan;
- dromos burials (more recent) normally regular in the form of a T or with a centrypetal development.
The tombs architecture is often enriched with details inspired by the houses of the living (steps, pilars, frames, false architraves,etc), by taurine horns, false doors and incisions in the most spacious rooms, these most likely destined to funerary rituals. The notable quantity of finds have revealed archeological remains dating from the Culture of Ozieri (Late Neolithic 3300-2900 bC) testifying the life of the first users; and the use of the necropolis terminated with the Culture of Bonnanaro (Early bronze Age about 1800-1600 bC). The domus de janas, sealed on the outside by stone slabs, revealed the presence of a series of burials ranging from two up to thirty individuals, in either primary or secondary inhumation, and some rare cases of semicombustion. Some tombs have also revealed remains of offerings and meals consumed in the large cellae or close to the entrance.

The pre-Nuragic Necropolis complex is situated
10 km from Alghero, on the road which
leads to Porto Torres.