The Hagia Sophia in Istanbul is unquestionably one of the most splendid monuments of human history.

It was built by the Emperor Constantine the Great in honor of the Holy Wisdom (Hagia Sophia is Aya Sofya in Greek and Turkish). Destroyed by fire in 404 and rebuilt by Emperor Theodosius II, it burned again during the Nika revolt in January of 532, along with other churches, the spa and the imperial palace. The Emperor Justinian decided a new reconstruction, completed in 537, with the project of the architects Anthemius of Tralles, famous mathematician, and Isidore of Miletus, who applied innovative building techniques. For 916 years he represented the largest church in Christendom. In 1453, when Constantinople fell into the Ottoman Turks, Hagia Sofia turned it into a mosque, adding the minarets. Many mosaics were then filled and covered with elegant traditional decor of the mosques. Desecrated by Ataturk in 1935, it is still one of the symbols of Istanbul, synthesis of the two different religious cultures of which it retains, as far as possible, the artistic and religious expressions of their respective eras.The church is the poster of the Byzantine architecture and represented the divine protection of the Empire. The bare and heavy exterior, with buttresses that support the building on all sides, contrasts with the sumptuous interior of imposing size. The land area is 7,570 square meters. Entering the church, the harmony of proportions, the profusion of columns and decorations wealth affect the people. The great dome with a crown of forty windows overlook the central square space, with niches alternately curved and straight, surrounded by aisles and the galleries. The height of the central dome is 55 meters, with a diameter of 32, an exceptional result for the sixth century construction techniques. At the center of the dome, a huge chandelier comes down to a few meters from the floor. Notable is the succession of half-domes covered with gold mosaics surrounding the majestic central dome. Most of the walls is covered with frescoes and mosaics, often depicting floral and geometric patterns. Among the most famous Byzantine mosaics, the one with Christ holding the Bible in his left hand and right hand raised in blessing, the Virgin with her Child between Emperor John Comnenus and the Empress Irene; on the inner door, the Virgin with the Child between Constantine the Great, who presents the model of the city, and Justinian, that offers the model of St. Sophia. To the sides, four huge medallions added in 1800 reported the names of Allah and Muhammad in Arabic script.