Ancient Heptapyrgion in Thessaloniki, Greece
Thessaloniki Sights & Monuments - The Ancient Heptapyrgion in Thessaloniki, Greece, also known as the Fortress of Seven Towers, stands above the Old Town (Ano Poli) and served as a Byzantine and Ottoman fortress. As the seat of the garrison commander until the late 19th century and a prison until 1989, the Heptapyrgion has a rich history. Since the prison's closure, restoration and archaeological work have taken place, making the site open to visitors today.