Hagia Sophia — the Wisdom of God, — The former cathedral, later — a mosque, now — a museum; the world famous monument of Byzantine architecture, symbol of the "golden age" of Byzantium. The official name of the monument today Hagia Sophia Museum (in Turkish: Ayasofya Müzesi).

In the days of the Byzantine Empire the cathedral was in the center, next to the Palace of the Emperor. Nowadays is located in the historic center of Istanbul, district Sultanahmet. In 1935, he acquired the status of a museum. In 1985, St. Sophia Cathedral, among other monuments of Istanbul's historic center was added to the UNESCO World Heritage List..

Over thousands of years the Sofia cathedral remained the biggest church in the Christian world - until the construction of the Cathedral of St. Peter in Rome.