The Hagia Sophia or the Hagia Sophia Holy Grand Mosque is a famous place of Islamic worship in Istanbul, Turkey. It was formerly the Church of Hagia Sophia until the Fall of Constantinople in 1453 when it was converted to a Mosque by the Ottomans. The structure itself was built in AD 537 and has remained intact since with architectural changes over the years such as the addition of minarets in the 15th and 16th centuries. Because of its longevity, it has seen the rise and fall of many empires and is deep with cultural and historical significance. This is one of the reasons why this site was recognized as an UNESCO World Heritage Site in 1985.