Hillfort of Santa Trega Nature · A Guarda, Baixo Miño, Pontevedra A walled settlement with gates to the north and south discovered in 1913 when a forest track was opened, and excavated by Ignacio Calvo between 1914 and 1923; its period of greatest splendour lies between the 1st century BC and the 1st century AD. It is the most emblematic and most visited of the Galician castros, declared a National Historic-Artistic Monument in 1931 and today a Bien de Interés Cultural (Spain's highest level of heritage protection). On several of the mountain's stones petroglyphs are preserved, carved two thousand years before the castro was settled. According to the thesis of Antonio de la Peña Santos, director of the last excavation campaigns in the 1980s, after the gradual abandonment that followed its splendour there may have been sporadic and temporary reoccupations as early as late Roman times. Photo: kilezz/QuiRóH (CC BY-SA 3.0) What to see and do in A Guarda