Su Nuraxi is situated on a small plateau at the foot of the Giara di Gesturi, in the Marmilla region. In 1997, this monument was declared a World Heritage Site by UNESCO.
The fortress was the main stronghold of a system which included other nuraghi set along the slopes of the Giara. Its keep had a base diameter of about 12 m, three floors and a roof terrace, and reached a height of almost 19 m. The chambers had corbelled ceilings. The keep is surrounded by four subsidiary towers linked by a massive stone curtain wall. These towers had two floors and two sets of loopholes. The keep, curtain walls and towers were crowned by stone brackets that supported terraces and ledges. A complex system of stairways and sloping passages within the walls, and ladders and mobile bridges provided access to the upper floors. The courtyard has a 20 m deep well, fed by spring water. The fortress is surrounded by a large hut village. At the end of the Iron Age, this complex was largely destroyed. Abandoned for a long while, it was subsequently re-utilised during Punic and Roman times (5th century BC – 3rd century AD) for living, funerary and sacred purposes.