University of al-Qarawiyyin
Founded in 859 by Fatima al-Fihri as a mosque with an attached school in Fez, Morocco, al-Qarawiyyin grew into a leading center of the Islamic Golden Age, drawing scholars including Ibn Khaldun and Maimonides. Guinness World Records calls it the 'oldest existing, and continually operating educational institution in the world'; it joined Morocco's state university system in 1963.