Heptapyrgion Fortress, Thessaloniki

The Heptapyrgion Fortress, also known by its Ottoman name Yedi Kule, meaning “Fortress of Seven Towers”, is a complex that actually includes ten towers, constructed in multiple phases over several centuries.

The northern section of the fortress incorporates earlier defensive elements, likely connected to Thessaloniki’s Late Roman fortifications of the 4th century, with substantial rebuilding during the Middle Byzantine period, particularly in the 9th century. The southern enclosure, including several of the towers that define the fortress’s present form, was probably added in the 12th century, when the city’s defenses were reinforced during a period of renewed military pressure.

After the Ottoman capture of Thessaloniki in 1430, the fortress was further modified and became an important administrative and military center. Under Ottoman rule, Heptapyrgion functioned as the seat of the military governor and remained a key stronghold overlooking the city and the Thermaic Gulf.

From the late 19th century, the fortress was converted into a prison, a role it retained well into the 20th century. It housed common criminals as well as political prisoners, particularly during periods of political repression, including the Second World War and the Greek Civil War. The prison was officially closed and relocated in 1989, ending one of the darkest chapters in the site’s history.

Following the prison’s closure, the Greek Ministry of Culture assumed responsibility for the complex and initiated restoration and conservation work. Today, visitors can walk through the fortress grounds, explore its towers and courtyards, and take in wide panoramic views over Thessaloniki.