The defensive walls are one of Niebla’s characteristic features. They are designated cultural property, and their origins go far back in history. Remains of at least two pre-Roman enclosures have been found, which could date back as far as the 9th-5th centuries BC. The Romans and Moors also left their mark on this structure. The walls have undergone various changes and modifications throughout successive conquests and periods of history. They have 46 square towers, two octagonal ones and various access gates.