The “Church of Holy Wisdom”, Hagia Sophia is among the world’s greatest architectural achievements. More than 1,400 years old, it stands as a testament to the sophistication of the 6th-century Byzantine capital and had a great influence on architecture in the following centuries. The vast edifice was built over two earlier churches and inaugurated by Emperor Justinian in 537. In the 15th Century the Ottomans converted it into a mosque: the minarets, tombs, and fountains date from this period. To help support the structure’s great weight, the exterior has been buttressed on numerous occasions, which has partly obscured its original shape.