Anadolu Hisarı, located on the Asian side of the Bosphorus in Istanbul, is a small yet historically significant fortress built in the late 14th century by Ottoman Sultan Bayezid I. Constructed to control naval traffic on the Bosphorus, it played a key role in the Ottoman conquest of Constantinople. The fortress, made of stone walls and a central tower, sits at the narrowest point of the strait, directly across from Rumeli Hisarı, which was built later to complete the Ottoman stronghold. The fortress has been recently renovated and open to public as a museum, while hosting some events and concerts from time to time. Anadolu Hisarı offers visitors a glimpse into Istanbul’s medieval past, set against the scenic backdrop of the Bosphorus.