During opening hours you can walk in here freely to see the magnificent old Muslim prayer hall with its beautifully decorated prayer niche, or mirhab. It has undergone so many architectural changes it's hard to believe it was once a Moorish-style university and school of Islamic studies founded by sultan Yusuf I in 1349. Famous graduates include the poet Ibn Zamrak. The original façade was made of marble and inscribed in Arabic with scientific and philisophical theories. The main mosque was next door, now the cathedral and the surrounding area was the market place, or Alcaicería. The Catholic Monarchs turned it into the Town Hall in 1500. Its now part of the university's literature faculty and also houses a Fine Arts Academy where there are occasional exhibitions. Admission: free