were carried out on the mosque structure and in the Courtyard of the Oranges by Félix Hernández between 1931 and 1936. More recent scholars have noted that modern restorations since the 19th century have partly focused on "re-islamicizing" (in architectural terms) parts of the Mosque-Cathedral. This took place in the context of wider conservation efforts in Spain, starting in the 19th century, towards studying and restoring Islamic-era structures. The Mosque-Cathedral was declared a UNESCO World Heritage Site in 1984, and in 1994 this status was extended to the entire historic centre of Cordoba. A restoration project began on the bell tower in 1991 and finished in 2014, while the transept and choir of the Renaissance cathedral were also restored between 2006 and 2009. Further restorations of features like chapels and some of the outer gates have continued to take place up to the late 2010s. Architecture The Great Mosque of Córdoba held a place of importance amongst the Islamic community of al-Andalus for centuries. In Córdoba, the Umayyad capital, the Mosque was seen as the heart and central focus of the city. Muhammad Iqbal described its interior as having "countless pillars like rows of palm trees in the oases of Syria". To the people of al-Andalus "the beauty of the mosque was so dazzling that it defied any description." After all of its historical expansions, the mosque-cathedral covers an area of . The building's original floor plan follows the overall form of some of the earliest mosques built from the very beginning of Islam. Some of its features had precedents in the Umayyad Mosque of Damascus, which was an important model built before it. It had a rectangular prayer hall with aisles arranged perpendicular to the qibla, the direction towards which Muslims pray. It has thick outer walls with a somewhat fortress-like appearance. To the north is a spacious courtyard (the former sahn), surrounded by an arcaded gallery, with gates on the north, west, and east sides, and fountains that replace the former mosque fountains used for ablutions. A bridge or elevated passage (the sabat) once existed on the west side of the mosque which connected the prayer hall directly with the Caliph's palace across the street. Al-Razi, an Arab writer, speaks of the valuable wine-coloured marble, obtained from the mountains of the district, which was much used in embellishing the naves of the mosque. The Christian-era additions (after 1236)