The Hagia Sophia was once the world’s largest domed building and has served as a church, mosque, and museum before being reconverted into a mosque in recent years. This rich history makes it a unique architectural and cultural treasure. Inside, both Islamic calligraphy and Christian mosaics stand as prized artistic gems. Large Islamic engravings adorn the towering stone columns, while natural light pours in through 40 windows, enhancing its grandeur. A masterpiece of Byzantine architecture, the Hagia Sophia has undergone various additions over the centuries, making it one of the most iconic landmarks in Istanbul and Turkey.