1. Hagia Sophia, Istanbul
Two churches with the same name, where the Hagia Sophia stands today, have disappeared for different reasons. The building, commissioned by the Eastern Roman Emperor Justinian in 537 BC, is one of the masterpieces of Byzantine architecture. Covering an area of 7570 square metres, the Hagia Sophia astounds with its dimensions and external appearance. Its fascinating interior draws the eye with its domes, columns and mosaics, the centrepiece of which is the vast dome that gives the impression of floating in the air. The Hagia Sophia, which was converted into a mosque with minarets after the conquest of Istanbul in 1453 and is now open for religious services, is also the source of many legends.