Hagia Sophia is a global architectural masterpiece standing in Istanbul, the largest city in present-day Turkey. In Greek, "Hagia Sophia" means "Holy Wisdom," symbolizing God's wisdom in Christianity.

The structure, as it is known today, was rebuilt on the same site three times. The current remaining structure was completed in an astonishingly short period, from 532 to 537, by order of Emperor Justinian I during the zenith of the East Roman Empire (Byzantine Empire). It served as the cathedral for the Archbishop of Constantinople (present-day Istanbul) and was the largest Christian church in the world for about 1,000 years. Its design was undertaken by two scientists, the architects Anthemius and Isidorus, and is particularly characterized by its enormous dome, which spans about 31 meters in diameter. This dome is technically highly innovative, possessing a unique structure that appears to be suspended from the ceiling.

When the Ottoman Empire conquered Constantinople in 1453, Sultan Mehmed II converted the Hagia Sophia into an Islamic mosque. At this time, minarets and large Islamic calligraphy (such as circular Arabic script disks) were added to the building, but many of the sumptuous mosaics from the Christian era were covered with plaster and thus preserved. Throughout the Ottoman era, the building continued to be used as a first-rate mosque for about 500 years.

Subsequently, upon the establishment of the Republic of Turkey, the Hagia Sophia was opened as a museum in 1935 under a policy of secularism. This transformed it into a rare cultural heritage site, attracting tourists from all over the world with the parallel existence of art and decoration from both the Christian and Islamic periods. However, a decision by the Turkish government in 2020 designated it for use as a mosque once again, sparking international debate about its religious and cultural status.

Due to its magnificent appearance and complex history of transitions, the Hagia Sophia continues to hold an important position as a representative work of Byzantine architecture and as a historical symbol where Eastern and Western cultures intersect.