Built on opposite sides of the Dardanelles Strait, the Kilitbahir and Çanakkale (Cimenlik) fortresses played a key role in the capture of Constantinople (1452), and again during the battle here in 1915 during the First World War. Kilitbahir, round in shape, is more beautiful than its Asian sister: it is extended via a curtain wall to a second clover leaf tower shaped almost like a heart, dominated by a massive keep in the centre of the courtyard.