Murallas de Niebla comprises an Almohad-era walled town and fortress, one of the best-preserved fortified precincts in Europe. The defensive perimeter extends 2 kilometres around the historic town, reaching maximum heights of 16 metres and featuring 50 square towers and six access gates, enclosing approximately 16 hectares. Originally constructed after the Muslim conquest in 711, the walls saw destruction and reconstruction, with most of the current structure dating to the 15th century. Five fortified gates—including the famous Torre del Oro—provide access, and at least 40 defensive towers remain visible, offering visitors an exceptional view of medieval Islamic fortification engineering.