The Heptapyrgion, otherwise known as modern Eptapyrgio or more popularly as its Ottoman Turkish name Yedi Kule, is a Byzantine and Ottoman-era fortress located on the north-eastern sector of the acropolis of Thessaloniki city in Greece. Its name directly translates to ‘Fortress of Seven Towers’ in both Greek and Turkish but in actual fact, it comprises of ten! It was perhaps named after the Yedikule Fortress in modern Istanbul.

The fortress was built as a redoubt of the city’s acropolis as well as where the Ottoman garrison commander would be seated - this continued till the late 19th century when the building was then remade into a prison until 1989. Refurbishment and archaeological excavations have begun in the compound since the 1970s and continue up till today!