Many monolithic door jambs and lintels have been found decorated with intertwined geometric shapes and rope-like moulding. In addition, embedded in the walls, cylindrical monolithic blocks of small dimensions have been found decorated with geometric shapes such as spirals, triskelions, Celtic roses, or pinwheel designs. Other elements such as plinths present similar decorations in addition to representations of animals. With regard to roof structure, archaeological findings do not support the traditionally observed system of a conical roof supported by a central post. In the place where a hole to fix the central post would have been found, archaeologists instead discerned evidence of ‘lareiras’ or hearths, suggesting a roofing system that distributes the weight directly onto the walls rather than a post. Not all of the stone structures discovered at Castro de Santa Trega served a residential purpose. In particular, one type of building appears to be storehouses which possess a less elaborate and less careful construction than the neighbouring houses. Inside these buildings, remains of amphoras, a mill, carving stones, etc. were found. The urban distribution of the settlement is characterized by groups of buildings forming individualized clusters. These clusters are known as “family or household units” and are formed by dwellings and storehouses set around a small, often paved, communal courtyard. The site's urban planning includes a complex network of rainwater drainage channels located under the pathways, as well as sometimes on the surface, sculpted on the base rock and covered with slabs. Sometimes these waters were channelled into tanks built into the rock and covered with a weatherproof mortar. Proof of a human presence approximately 2,000 years prior to the settlement's construction is confirmed by the petroglyphs or rock engravings left in various locations in that area. Many of these petroglyphs were concealed by structures raised during the construction of the fort. The ‘Laja del Mapa’, also known as the ‘Laja Sagrada’ [Sacred Rock], is the better known of the geometric representations that are still visible. Situated on the highest part of the hill, the engraving is made up of various spirals, concentric circles and roughly parallel lines. It is evident that these engravings have no relation to the fort, since they are a product of a society that developed 2,000 years before, during the final stage of the Galician Neolithic period. As is the case with many Galician forts, a large quantity of ceramics has been recovered.