Hagia Sophia is a great and historical museum in Istanbul, Turkey. It’s very close to another great historical structure in Istanbul, Sultan Ahmet Mosque. There is no exact evidence when was Hagia Sophia was built and who built that great structure, but history experts think that Hagia Sophia was built before the year of 1000. Hagia Sophia had served as a church until Ottoman conquered the Istanbul city at 1453. After Ottomans conquered the Istanbul, Hagia Sophia was tuned into a mosque at the year of 1453 and it served as a mosque for several years.