 |  Ruina montium |
 Inner and exit of a tunnel. |
Las Medulas is not only a very important archaeological area; it is also a Cultural Landscape: the result of Roman occupation of a land and its evolution and changes through the years. Monumental remainings of Roman activity on mines are the most interesting things on the area, but we should never forget Preroman age, reminded by two astur castra on this land.
Many axes, some pottery, points of arrow and lance, few remainings until the age of Bronze, when images of idols appeared, did survive.
At the Iron Age Castrena culture began. At Las Medulas, it is represented by both castra named before: Castrelin of San Juan de Paluezas and castra of Borrenes. These communities worked surrounding lands and took gold for their own needs, decoration and tools.
After Roman conquest -Cantabrian wars (28-19 b.C.)- it became an "industrial" exploitation. Romans, through witty systems, took big quantities of gold until the end of 2nd. century. “Arrugia” method or “ruina montium” consisted of building a raft for retaining water that communicated with several galleries excavated inside the mountain. After leaving water free, it provoked the fall of earth blocks, that came to washing canals: the “agogae”.
About both castra remainings, we point out that they were placed on strategically dominant positions. They had defensive walls, usual in these populations.
 Zenithal view  Castrelin of San Juan de Paluezas |
- Castrelin of San Juan de Paluezas
It was walled. Model-houses structure shows divisions in areas: one for living; a patio as a hall; a storage area and another one for working. It was built of stone with a wooden and straw waterproof cover.
Plan for typical house from San Juan de Paluezas castra
- Castra Borrenes
It is endowed with an impressive unfinished wall, since Romans took the area before it was finished. Probably this castra was never inhabited. People who built it with big walls and a pit -probably to fight against Romans- were taken to another village closer to the gold mines in order to make them work like slaves.
 House from castra of Borrenes |
 Wall from castra of Borrenes |