Al-Qarawiyyin Mosque, founded in 859 AD, houses the world's oldest continuously operating university. Established by Fatima al-Fihri as a small mosque, it evolved into a leading educational center in the Islamic world. The mosque accommodates 20,000 worshippers and features a magnificent marble courtyard, square minaret, and library containing rare manuscripts. Non-Muslims cannot enter but can glimpse the courtyard through the gates. The library was recently restored and has become partially accessible to visitors.