The Giralda is the bell tower of the Cathedral of Seville. Its height is 343 feet (105 m), and its square base is 23 feet (7.0 m) above sea level and 44 feet (13 m) long per side. The Giralda is the former minaret of the mosque that stood on the site under Muslim rule, and was built to resemble the minaret of the Koutoubia Mosque in Marrakech, Morocco. It was converted into a bell tower for the cathedral after the Reconquista,[7] although the topmost section dates from the Renaissance. It was registered in 1987 as a World Heritage Site by UNESCO. The tower is 104.1 m in height and was one of the most important symbols in the medieval city. Construction began in 1184 under the direction of architect Ben Ahmad Baso. According to the chronicler Ibn Sahib al-Salah, the works were completed on 10 March 1198, with the placement of four gilt bronze balls in the top section of the tower. After a strong earthquake in 1365, the spheres were missing. In the 16th century the belfry was added by the architect Hernán Ruiz the Younger; the statue on its top, called "El Giraldillo", was installed in 1568 to represent the triumph of the Christian faith.