The Blue Mosque is the most famous mosque in Istabul. It is in the centre of the Old City, just down the street from Hagia Sofia. Its 6 minarets (which make it very unique as most have 4) were built by mistake. The ruling sultan instructed the architects to build 'gold' minarets, not 'six' but the Turkish word is almost the same and so there was some confusion. The name of the mosque comes from the blue ceramic mosaics that cover the insides. Very beautiful!