Mosque–Cathedral of Cordoba (Spain)
For a period of time, this place of worship was shared by Christians and Muslims. However, as the Muslim population increased, the Muslim rulers turned it into a mosque. During the Reconquista in the 13th century, the mosque was reclaimed by the Christians and it was transformed into a cathedral.
It is a wonderful showcase of Renaissance and Moorish architecture and definitely worth visiting. The complex consists of the courtyard with a minaret and the prayer hall. The most notable part of the building is probably the hypostyle hall with 856 columns taken from the Roman temple which stood here before.