Rumeli Fortress is between Baltalimanı and Bebek, on the European side of the Fatih Sultan Mehmet Bridge (also known as the 3rd Bridge), which connects Europe and Asia. It is within the boundaries of Sarıyer district. It was a military fortress built by Sultan Mehmet the Conqueror before he conquered Istanbul. It was built in the last phase of the Middle Ages, one year before the Byzantine Empire vanished into history.
It was a building that, with the Anatolian Fortress right across it, aimed to cut the Istanbul-Black Sea connection, causing a serious blow to the Byzantine Empire's all communication and assistance opportunities that could come from the north. The base where the Janissaries were stationed targeted the ships that wanted to enter the Bosporus from the Black Sea with artillery fire. With a sunken Venetian ship, the hopes of supporting Byzantium from the north by sea had also ended.
After the conquest of the city in 1453, it lost all its military function. After this date, it was used as a prison. Especially foreign ambassadors and prisoners of war were kept here. The Rumeli Fortress, located in a deep valley with its asymmetrical dimensions of 250x150 meters, has three big towers and high bastions. In an inscription in Arabic script there is information indicating that its construction was completed in “H. Recep 856” or 1452.
As part of the celebrations held in honor of the 500th anniversary of the conquest of Istanbul, the Rumeli Fortress was renovated in 1953 and was transformed into a stage and park area where concerts were held until 2008. However, today it is closed to activities because it may damage the historical structure. It offers the function of an open air museum; and cannons used in the conquest can be seen. Behind the scene covered with plants, there is also a mosque ruin that keeps the historical atmosphere alive.