Prior to construction of the Fatih Sultan Mehmet Bridge in the 1980s, this massive fortress was the major landmark on this part of the Bosphorus. Built by order of Mehmet the Conqueror in 1452 at the narrowest point of the strait, it and Anadolu Hisarı, the castle that had been built on the opposite shore in 1393–1395, enabled the Ottomans to control all water traffic, cutting the city off from resupply by sea and contributing significantly to the Ottoman defeat of Byzantine Constantinople.
Legend tells us that to speed Rumeli Hisarı's completion, Mehmet ordered each of his three viziers to take responsibility for one of the three main towers. If a vizier's tower construction was not completed to a tight four-month schedule, he would pay with his life. Needless to say, the work was completed on time.
The useful military life of the fortress lasted less than one year. After the Conquest of Constantinople, it was used as a glorified Bosphorus toll booth for a while, then a military barracks, a prison and finally an open-air theatre.
Within the walls are ill-kempt grounds and the minaret of a ruined mosque. Steep stairs (with no barriers, so beware!) lead up the ramparts; the views from here are magnificent.
Next to the fortress are the Rumeli Hisarı bus stop and a clutch of cafes and restaurants that are particularly busy on weekends.
