Agia Sofia, also known as Hagia Sophia, is a historic architectural marvel located in Istanbul, Turkey. Originally built as a cathedral in 537 AD during the reign of the Byzantine Emperor Justinian I, it served as the center of Orthodox Christianity for nearly a thousand years. Its massive dome and intricate mosaics showcase the artistic and engineering achievements of the Byzantine Empire. In 1453, after the Ottoman Empire conquered Constantinople, Agia Sofia was converted into a mosque. It remained a mosque for nearly 500 years until it was secularized and turned into a museum in 1935. In 2020, it was reconverted into a mosque, continuing to be a symbol of cultural and religious significance.