Oval enclosure with ample terraces to the west and a large ditch to the east. This castro (a hillfort settlement) was most likely occupied many centuries ago, but the remains of the structures date back to around 600 BCE, because this was when stone began to be used for construction. Like many others in Galicia, this castro reached its peak during the 1st and 2nd centuries CE. It measures approximately 200 metres east to west by 150 metres north to south. It has a complex defensive system composed of an outer wall, a ditch and a rampart. The wall varies in width from 1.5 to 5.5 metres and is between 2 and 5 metres high. It has a tower on the east part, one of the only examples of its kind in the northwest of the peninsula. The entrance of the hillfort has an 18-metre deep and 10-metre wide ditch dug into the rock and currently it is used as a path that gives access to the castro. Two small gaps in the rampart protect the northeast part of the castro. Made of earth and stone, they are 6 metres long and 3 metres high. Around 30 houses of circular, oval, square and rectangular shapes have been excavated on this site. An important part of the castro is the Serpe de Troña, a petroglyph depicting a serpent in a heraldic pose. It is carved into the vertical face of a stone in one of the houses