Southeast of Santigoso is the Alto del Castelo, a fabulous viewpoint over the town. At a lower level to the south, we find a huge castro datable to the final phase of the Iron Age (2nd century BC – 1st century AD) corresponding to the final phase of the culture of the Galicians. This fortified village is formed by three enclosures that have good natural defenses, except in the northern sector, where its inhabitants erected a field of standing stones to hinder the attack. El Castelo Pequeno is located on an acropolis, a hill crowned by a natural granite outcrop or “castelo”, at 1254 meters of altitude, situated in the middle of the Serra da Azoreira. It is the highest and most visible castro in the entire area. From the north, where the so-called Castelo Grande (1,249 m) is located, its visual domain is vast, controlling not only the plains and valleys of A Mezquita but also a good part of the Terra das Frieiras, part of the Portuguese lands of Tras os Montes, and the Zamoran lands of Lubián and Hermisende. The place where it is located is a high mountain erosion surface, with many granite outcrops throughout the area, barren and inaccessible, with poor soils of little depth and no river, only tributary streams of the Cádavos river. The castro is located in an area suitable for livestock and grazing, but it does not seem to be a settlement dedicated solely to the agricultural economy if we consider its enormous size and the wide visual control it has over the territory. Each of the three enclosures is flattened on strong embankments and walled with granite stone walls, which in the croa (the upper enclosure), despite the plundering, the collapses reach a height of about 10 meters. In the third enclosure, facing southeast, the wall is 4.30 meters wide and features a construction model in horizontal rows of polygonal apparatus filled with masonry, similar to that of the large castros in the neighboring region of Monterrei. The Castillo Pequeño de Santigoso, with dimensions between 9.5 and 10 hectares, is, along with San Cibrán de Lás, one of the largest castros in Galicia after Santa Tegra (20 hectares). During the Iron Age, the average population of the castros in the northwest of the peninsula was about 200 people and little more than 1 hectare. Strategically located, each village was built in isolation to avoid interfering with the development of other fortified villages and thus avoid conflict over the dominance of natural resources. The small castros disappear with the arrival of the Roman troops. Thus, the large castros of the Northwest emerge, like this one of Castelo Pequeno, which could be the result of the union of several small communities seeking to form a larger political entity to face the new reality.