The Andalucian city of Cordoba is home to the Mezquita, the most elaborate mosque in Moorish Spain. 

This 10th century mosque boasts an eye-popping 850 granite and marble pillars and was built to hold up to 20,000 worshippers. Although many of the original Islamic architectural features are still evident, the centre of the mosque was overtaken in the 16th century by a Renaissance cathedral.