The Mezquita is Córdoba, Spain's most famous attraction. It is a mosque built by Spain's Moorish occupants starting in 785 and continuing, with sections built under four Moorish emirs until 987. It was built on the site of an earlier Visigothic church, and was one of the largest mosques in the world. Today it is still the third largest, as well as the largest mosque in the Western world, although it no longer serves its original purpose.
Its oldest sections, built between 785 and 787, were built out of sandstone and brick (whose softness allows it to withstand earthquakes), and later sections were built of sandstone and marble. Like most Moorish mosques, it features a Patio de los Naranjos, a courtyard planted with orange trees and small fountains as Muslim philosophers and clerics believed that the sound of water flowing was conducive to concentration. Inside more than 850 red- and white-striped columns form arches that support the ceiling. Since the original section was to be built very quickly, some of the columns were cannibalized from churches and Roman buildings, and sunk into the ground or placed on pedestals to even them out. Its walls are heavily decorated in the familiar geometric patterns that grace most mosques.
One of the oddest features of the mosque is its dazzingly ornate Mihrab. This is the niche that illustrates the direction of prayer, and normally faces toward Mecca. Perhaps because of nostalgia, Abderramán I, the monarch who originally directed the building of the structure, ordered it to point in the direction of his birthplace of Damascus. The Mihrab is also not in the center of the building, as is ordinarily the case, because when it was expanded the river Guadalquivir and a nearby palace obstructed its growth except towards the West.
In 1236, during the Reconquista, the city was retaken by the Catholics but the Mezquita was allowed to stand in recognition of its great beauty, consecrated as a cathedral. In 1371, the small royal chapel, or Capilla Real, was built inside. In 1523, against the wishes of the leaders of the town, the Bishop of Córdoba and King Charles II put into action the construction of a large cathedral in the traditional style within the walls of the mosque. It took 234 years and combined Gothic, Baroque, and Renaissance building styles. They removed some of the columns, relocating them, and raised the ceiling in portions of the mosque, and with the usual Catholic excess of the era, filled the cathedral with gold, destroying or altering most of the building. It's said that when Charles II visited the city later, during the construction of the cathedral, he spoke of his regret in allowing damage to be done to the unparalleled architecture of the building.
During various points in its history, the Mezquita has housed bones from the prophet Muhammad's arm and even the original Qur'an. Today the Mezquita stands as perhaps the oldest and best preserved example of Moorish architecture, and in fact of Muslim architecture in general of the era. It is magnificent and one of the premier tourist sites in Spain, besides its role as a cathedral.