Cairo (/ˈkaɪroʊ/ KY-roh; Arabic: القاهرة, romanized: al-Qāhirah, pronounced [ælqɑ(ː)ˈheɾɑ]) is the capital of Egypt and the largest urban agglomeration in Africa, the Arab world and the Middle East. The Greater Cairo metropolitan area, with a population of 21.9 million, is the 12th-largest in the world by population. Cairo is associated with ancient Egypt, as the Giza pyramid complex and the ancient cities of Memphis and Heliopolis are located in its geographical area. Located near the Nile Delta, the city first developed as Fustat, a settlement founded after the Muslim conquest of Egypt in 640 next to an existing ancient Roman fortress, Babylon. Under the Fatimid dynasty a new city, al-Qāhirah, was founded nearby in 969. It later superseded Fustat as the main urban centre during the Ayyub