The archaeological area is located in the center of the basaltic plateau of Pranemuru, in a position of wide domination over the course of the Flumendosa, in the Sarcidano region, in central-southern Sardinia.
Arrubiu (arrubiu = “red”, the color of basalt) is one of the most important and impressive nuraghs on the island. It is the only pentalobate known to date. It is built at the base with large basalt blocks on which rest regular rows of smaller boulders reinforced with wedges and abundant mud mortar.
It consists of a keep (A) surrounded by a bastion of 5 towers (B-G) and an antewall of 7 towers (H-P), perhaps originally larger, which delimits 3 courtyards.
The keep, originally with two floors and a terrace (residual height m 14; original height m 25-30) preserves the lower tholos and part of the first floor chamber (diameter m 4), as well as a small domed room with access from the outside that had the function of lightening the wall mass.
The lower room (height 11 m) is accessible through an S-facing entrance and a flat walkway (length m 3.40; width m 1.08). It has the intact tholos and three irregular niches arranged in a cross. He returned a large fireplace and, buried in the center, a globular vessel with microfractures perhaps intended for the dispersion of liquids for ritual purposes.
Without a gateway, the keep could be reached to the upper levels from the stands of the bastion through a spiral staircase carved into the thickness of the D-E curtain, almost on the entrance of the bastion.
The entrance leads to the central courtyard, polygonal (9.90 m x 6.80 m), with a platform along the right side, a tank and an adjoining canalization system. The courtyard is overlooked by the coaxial tower D and the keep, the front side towers E and C, a niche, the corridor connecting with the rear towers G and F, and a staircase for access to the stands. In corner N, a small domed compartment (diameter 0.80 m) has been carved into the masonry of the lower chamber of the keep with the function of structural lightening.
Tower D (height 6.60 m) preserves the tholos intact. Tower F is preserved for two-thirds of its original height and has numerous loopholes: it was connected to the central courtyard and to tower G through two corridors spared in the curtains F-E and F-G.
Towers G and E are built at the base with large square blocks placed like a knife.
Tower E, with access from the central courtyard, preserves the circular inner compartment (height 6 m) with two niches and numerous loopholes. On the knife blocks of the base there are lintels that create five shelves. In front of the slits is a paved area delimited by knife plates.
The antewall (residual height max. m 3.20) connects 7 towers (towers H and N tangent to towers C and F of the bastion) and encloses 3 courtyards (K-Y). These were accessed through arched entrances and narrow backs, and with intrauterine stairs connected to the top of the curtains and terraces of the city towers. The curtains have niches, a counter and numerous loopholes partly occluded in ancient times.
In the courtyard Y there is a room - in a drop shape - that encloses a tall silos, and a semicircular hut with a central fireplace.
In the village that extended around the antewall, 3 huts have been excavated: among these a probable - meeting hut - (diameter 10 m) equipped with a counter.
The excavation data, although partial, lead to the date of the settlement between the final stages of the Middle Bronze and the Final Bronze. At the beginning of the Iron Age, life came to an abrupt end.
On the collapse of the central courtyard and the K1 courtyard, in the 2nd century BC, and until the 5th century AD, rooms were built for winemaking and other agricultural activities, as evidenced by rectangular tanks with channel-pouring channels, presses and basins.
A small row-chamber tomb of giants (length m 6; width m 1; height m 1) is located about 800 m N-W of the complex.

History of excavations
Since 1981, the site has been affected by excavation and consolidation, carried out by Fulvia Lo Schiavo and Mario Sanges. Archaeological investigations are still in progress.

Bibliography
E. Contu, "La fortezza nuragica di Nuraghe Orrubiu presso Orroli (Nuoro)", in Studi Sardi, X-XI 1950-51, pp. 120-160;
Progetto "I Nuraghi". Ricognizione archeologica in Ogliastra, Barbagia e Sarcidano, Milano, Consorzio Archeosystem,1990, pp. 100-101;
F. Lo Schiavo-L. Vagnetti, "Alabastron miceneo dal Nuraghe Arrubiu di Orroli (Nuoro)", in Rendiconti dell'Accademia dei Lincei, IX, 1, 1993, pp. 121-148;
F. Lo Schiavo-M. Sanges, Il Nuraghe Arrubiu di Orroli, collana "Sardegna archeologica. Guide e Itinerari", Sassari, Carlo Delfino, 1994;
F. Lo Schiavo, "Il nuraghe Arrubiu di Orroli", in L'eredità del Sarcidano e della Barbagia di Seulo: patrimonio di conoscenza e di vita, a cura di M. Sanges, Sassari, B&P, 2000, pp. 183-189;
La vita nel nuraghe Arrubiu, Dolianova, Comune di Orroli, 2003.

How to get
There From Cagliari, take the SS 131, direction Sassari. After passing the town of Monastir, leave the SS 131 and take the SS 128, direction Senorbì. In Senorbì, follow the signs for Suelli, Mandas and Isili. At the junction of Isili, leave the SS 128 and take the SS 198 until the junction for Nurri; turn right up the SP 10 and reach the town, crossing it until you reach Orroli. Continue on the same provincial road in the direction of Escalaplano; at km 9 you turn south into a road - marked by a tourist sign - that leads, after about 3.5 km, to the archaeological area equipped with a ticket office.