They were built with megalithic boulders as long as almost two meters, and the three gateways to the city, perfectly oriented to the three most significant sunsets of the year: the summer solstice sunset (Porta Spada, azimuth 301); the winter solstice sunset (Porta Trapani, azimuth 240); and the sunset at the spring and autumn equinox (Porta Carmine, azimuth 270).
To the large, older blocks that characterize the lower part, an elevation of smaller ashlars was added in later periods. The walls had watchtowers, a walkway accessed by steep steps and small openings that allowed the passage of inhabitants and perhaps supplies. The best preserved section runs along Via dell’ Addolorata, from Porta Carmine to Porta Spada.
