In 1523, the cathedral authorities - opposed by the city council but backed by King Carlos of Castile and Aragon - began building a massive chancel and choir, in very middle of the mosque. How bizarre a decision this was is best seen from an aerial photo. It's as if a typical soaring Gothic/Renaissance-style cathedral has suddenly fallen from the sky into the middle of a flat-roofed rectangular, Mecca-facing mosque.Apparently Carlos had never seen the mosque beforehand, but when he came to Cordoba for the unveiling of the new parts of the cathedral, he reportedly said in disgust: "You have built here what you might have built anywhere, but you have destroyed what was unique in the world."And, yet despite the horror of that decision to build something so absurdly out of place in the middle of such an original building, I have to admit - wandering around the cathedral-mosque is a wondrously giddy, ridiculously over-the-top, utterly magical experience.