Cairo has the oldest and largest film and music industries in the Middle East, as well as the world's second-oldest institution of higher learning, Al-Azhar University. Many international media, businesses, and organizations have regional headquarters in the city; the Arab League has had its headquarters in Cairo for most of its existence.
With a population of over 9 million spread over 3,085 square kilometers (1,191 sq mi), Cairo is by far the largest city in Egypt. An additional 9.5 million inhabitants live in close proximity to the city. Cairo, like many other megacities, suffers from high levels of pollution and traffic. Cairo's metro, one of two in Africa (the other being in Algiers, Algeria), ranks among the fifteen busiest in the world, with over 1 billion annual passenger rides. The economy of Cairo was ranked first in the Middle East in 2005, and 43rd globally on Foreign Policy's 2010 Global Cities Index.