Nothing gold can stay. Best wishes, John Green. Baghdad wasn't the only center of learning in the Islamic world. In Spain, Islamic Cordoba became a center for the arts, especially architecture. This is perhaps best exemplified by the Great Mosque at Cordoba, built by the Umayyad ruler Abd al-Rahman I in 785-786 CE. That's right, this building, still standing today and one of the most amazing mosques in the world, was built in a year, whereas medieval cathedrals took like a million years to finish. The Muslims of Spain were also engineers who rivaled the Romans.