The archaeological site of Castromao is located on a hill above the place of Santa María de Castromao, at an altitude of 732 meters, about two kilometers from the town of Celanova. It is one of the main references of the Castro culture in the Northwest of the peninsula. Numerous excavations and investigations have been carried out in this castro, thanks to which we can ensure that it has had a long presence over time. These excavations also reveal more than 70 occupational structures, defensive structures, such as the wall or retaining walls, and even part of a paved street. It dates from the Iron Age from the 6th or 5th centuries BC to the 2nd century AD, while the lower parts show an intense Romanization especially during the 1st and 2nd centuries AD. It is surrounded by a wall with a length of 485 meters. The walled area covers a surface of about 20,000 square meters, with a maximum axis of 150 meters. It features unique pieces such as the well-known Castromao trisquel, the tabula, the zoomorphic figure, or the coin hoard from the 1st century, which can be seen in the Provincial Archaeological Museum. At this site, it is possible to learn about the first settlements in the Northwest of the peninsula during the Bronze Age, and their evolution, such as the processes of adaptation of the structures to the new times.