The Hagia Sophia Grand Mosque, located in Istanbul, Turkey, is a historic site that has served as both a church and a mosque throughout its existence. Originally built in AD 537, it is known for its impressive architecture, including a massive dome and intricate mosaics. After being used as a cathedral and then a mosque, it became a museum in 1935 before being reconverted into a mosque in 2020. Despite its changing roles over the centuries, the Hagia Sophia remains a significant cultural and architectural landmark, attracting visitors from around the world.