The Fortress of Eptapyrgios, also known as the Ottoman name Yedi Kule, is located at the northeast end of the walls of Thessaloniki, within the Acropolis. It consists of two sections: the Byzantine fortress, which comprises ten towers between them and the corridor, as well as the newest prison buildings built inside and outside the fortress. The towers on the north side form part of the Early Christian wall of the Acropolis, while those on the south were probably added during the Middle Byzantine times, forming the closed core of the fortress.