You will explore Hagia Sophia, which is one of the world’s most iconic and historically significant buildings. Originally built as a cathedral by Emperor Justinian I in 537 AD, it was the largest cathedral in the world for nearly 1,000 years. After the Ottoman conquest of Constantinople in 1453, it was converted into a mosque and later became a museum in the 20th century, before returning to a mosque in 2020. Architecturally, Hagia Sophia is famous for its massive dome, which seems to float above the central nave. The interior features stunning mosaics, marble pillars, and Islamic calligraphy, blending Christian and Islamic art. The building symbolises the cultural and religious crossroads of Eastern Christianity and Islam, representing both the Byzantine and Ottoman Empires. Today, Hagia Sophia remains a major cultural landmark and a symbol of Istanbul’s rich, layered history.