What makes this site so especially fascinating, perhaps the most fascinating cathedral or mosque anywhere in the world, is that it really is both, and very aggressively so. Unlike the Hagia Sophia, which changes from a church to a mosque but looks exactly the same regardless (plus or minus giant black medallions), you literally can see fully intact parts of the mosque juxtaposed with the church. When Saint-King Ferdinand III conquered Cordoba in 1236 and converted the mosque back to a church, he left much of the mosque intact.