Arap Mosque hides a secret in plain sight: its minaret is a medieval bell tower, square and buttressed, unlike any other in Istanbul. Dominican friars raised the church in the early 1300s inside walled Genoese Galata, dedicating it to Saint Dominic — though locals always called it San Paolo, Saint Paul's. After the Ottoman conquest the church became a mosque, and Sultan Bayezid II later gave it to Muslims fleeing Spain after Granada fell. Those Andalusian exiles, called Arabs by their neighbours, gave the building its lasting name.
Step inside and the Gothic bones show through: a tall rectangular hall, a flat wooden ceiling laid over what was once a soaring nave, pointed windows no Ottoman architect would draw. Repairs a century ago even lifted the floor to reveal a Genoese graveyard sealed beneath the prayer carpet. Today the mosque stands quietly among Karaköy's hardware shops and coffee roasters, its pale tower rising over the lanes, holding centuries of prayer in a room that began as a friars' church.