In the northwest of the Iberian Peninsula rises a monumental legacy of ancient engineering with no parallels anywhere in the world. This grand defensive ring, which has retained its original layout for more than seventeen centuries, still encircles the historic center of one of Galicia’s cities. Its remarkable integrity and imposing appearance make it a true architectural gem, internationally recognized as an outstanding example of fortification from the time of the Empire.
This is the defensive perimeter of a city known in antiquity as Lucus Augusti. Its construction took place during the turbulent period at the end of the 3rd and beginning of the 4th centuries, when a powerful state faced internal crises and external threats. The main purpose of this cyclopean structure was to protect one of the key administrative centers in the northwest of the peninsula. A stone belt stretching over 2,120 meters, with walls ranging from 8 to 12 meters high and up to 7 meters thick, forms an impressive barrier enclosing about 34 hectares of the old quarter.
Initially, the defensive line was crowned by 85 towers, with five gates providing access to the city. Of these, Porta Miñá has survived to this day in the best condition. Today, after numerous reconstructions and adaptations to the needs of the growing city, 71 towers remain in place, and the total number of entrances in the defensive perimeter has reached ten. The construction was based on the treatises of the renowned engineer Vitruvius. Its massive walls, built from schist and granite and bonded with a mortar made of earth and pebbles, have demonstrated impressive resilience through the centuries. The perimeter, featuring semicircular bastions and straight sections between them, was once part of a comprehensive defense system that included a moat and an internal open area known as the intervallum.
In the 19th century, as urban development began to extend beyond the old city center, there arose a need for new entrances. However, unlike many other European cities, it was decided here not to demolish the ancient fortifications, but to integrate them into the new urban fabric. This is precisely what sets this fortification apart from all other ancient defenses, making it a unique example that has survived to this day in its original, unbroken form. Today, the upper part of the stone belt—the former patrol path—has been transformed into a public promenade. Walking along it reveals breathtaking views of the historic center, the cathedral, and the provincial museum. Covering nearly two kilometers means embarking on a journey into living history, connecting with the strength and ingenuity of engineers from a long-gone era. For a deeper understanding of the context in which this structure was created, a special interpretation center in the heart of the city helps visitors grasp the scale of the work accomplished and its role in the city’s evolution.
This is not just an archaeological site. It is a living symbol of identity and pride for the city that grew under the protection of its mighty stones, and a tangible reminder of the great legacy left on Spanish soil.
