The archaeological site is located on the “Taccu” of Osini, a suggestive natural fortress with steep limestone walls. It enjoys an exceptional visual dominance over Ogliastra and Barbagie.
The complex, particularly suggestive, includes a complex nuraghe with an adjoining village, a cave with two entrances, two tombs of giants and two single-tower nuraghes.
The nuraghe - built on the rock surface of which it encompasses the rough edges - is formed by a keep and three towers N-E, S and O. The towers are connected by a bastion, according to a lateral addition pattern. In the connecting curtain of the S and O towers, the entrance to the monument opens, which leads to an entrance with a niche on the wall of..
The entrance leads to a narrow curvilinear courtyard-corridor, with a paved floor, on which the entrances to the four towers overlook.
The keep - located in a higher position - is made of regular rows of blocks. The arched entrance, facing S-E (width. M 0.95-0.51; h m 1.80), introduces into a trumpeted andit (width. M 0.95-1.25; long. M 2.70; h m 1.80-2.80) with an angular cover of increasing height towards the room.
The stairwell opens upwards - preceded by a small hallway (width. M 0.95; h m 2.25) - which with 28 steps led to the upper floors.
The sub-circular room on the ground floor (diam. m 4-3; h m 5.50), preserves the ogival roof and the cobblestone pavement intact.
The upper room has an oval plan (diam. m 2.40-1.80; h m 1.55) with a stone slab floor. Two small closets open to the floor level.
The N-E tower (diam. m 7; h m 6), incorporated into the bastion, is attached to the keep. The structure contains a room - with a trapezoidal entrance (h m 2.90) facing S and raised by about 2.50 m on the corridor level - and a room below “tholos”, accessible from the floor of the room above by removing the terminal stone of the vault; it was perhaps a warehouse.
The upper room has a paved floor with a fireplace and a concavity at the entrance.
The O tower (diam. m 8; h m 6.50) has an entrance facing S-E that leads into a trumpeted entrance with a recess in the shape of.. The room (diam. m 4.60; h m 3.00) has six slightly raised slits next to which stone bases have been found that are difficult to interpret.
The S tower (diam. m 7; h m 3.30) has an entrance facing N-E (width. M 0.80-0.63; h m 2) that introduces a straight line. It enters the inner chamber (diam. m 3.80; h 3.50) equipped with seven thrombosed slits (width) M 0.70-0.40; h m 1.60-1).
In the town that extends around the nuraghe, eight rooms have been identified pertaining to blocks with a centripetal development.
The huts, circular (diam. m 8.50- 7), built with irregular rows of medium-small stones and abundant clay, have wall partitions and cobbled floors.
The complex of the nuraghe and the village was in use from the ancient Bronze to the final Bronze.
At this age, the cave below the archaeological area, which has two entrances on the side of Gairo Taquisara and Osini, was probably used as a warehouse for foodstuffs.
In the valley floor there is a row-shaped tomb of giants with curved steles, now buried. Another, very damaged, on the E side of the relief, is of the type with rows of blocks arranged in isodome technique.
The Sanu and Orruttu nuraghes, located in the plain of Troculu, a short distance from each other, are monotorri.
At the Orruttu Nuraghe there is a hut with a circular compartment and a rectangular atrium in front of the entrance hall.

History of excavations
The area has been affected in recent years by various excavation campaigns conducted by Maria Ausilia Fadda.

Bibliography
G. Lilliu, The Nuraghi. Prehistoric Towers of Sardinia, Cagliari, La Zattera, 1962, pp. 151-153;
M.G. Cabras, “Archaeology. The Nuraghe Serbissi. The Serbissi Cave”, in The Future of the Past by Osini. Archaeology, Environment and History, edited by M.A. Fadda, Nuoro, 2004, pp. 94;
C. Nieddu, “Nuraghe Serbissi”, in C. Nieddu (edited by) Archaeological Sites of Ogliastra, Tortolì 2006, pp. 44-45.

How to get There
From Tortolì, take the SS 125 in the direction of Jerzu, cross Bari Sardo and Cardedu and continue to the junction; turn right and take the SP 11 to Osini crossing Jerzu and Ulassai. You leave the town in the direction of the 'Taccu' of Osini and climb the plateau that overlooks the town, passing through the gorge known as the 'Scala di San Giorgo'. About 2.6 km away, there is a junction with a sign for the archaeological park. Turn right and continue for 1.6 km on a paved road. At the first fork, turn to D. and proceed on a dirt road for 3 km: the road stops at the foot of the path on the road that leads to the top of the hill, where the complex is located.