The name of Red Giant is due to its grandiose size and the hints of red lichens that colour its basalt stone walls. The complex of Nuraghe Arrubiu, in the territory of Orroli, stretches for five thousand square metres and consists of a central tower (fortified tower) that is 15 metres high - originally it was double this height - surrounded by a formidable bastion formed by five towers, in turn surrounded by a defensive wall with seven towers joined by curtain walls. Inside it there are various courtyards. To the southeast there is another defence wall with five towers joined by masonry. There are a 21 towers in total. Within the fortified wall, of which the first of three floors is still remaining, by walking along a narrow passageway, you will reach the central room, that contains a fireplace and a ritual vase. The (false) tholos roof is still intact, as in some of the smaller towers.