Eptapirgio Castle (14th-15th CENTURY)
At the top of the city stand the Trigonio Tower, with panoramic Thessaloniki below, and the Eptapirgio (“Seven Towers”) Castle, also known by its old Turkish name Yedi Kule, which, despite its present-day tranquility, ranks as one of the city’s most storied and colorful monuments.
Originally part of Theodosius I’s renovation (late 4th c. AD) of Thessaloniki’s Hellenistic/Roman city walls, Eptapirgio became an enclosed castle in the 12th century; then the Ottomans’ headquarters after 1430; and finally a notorious prison (late 19th c.), often referenced in Greek rebetiko songs, and a black hole for political prisoners.
 
It remained in use until 1989.
Below is one of the most famous references to the storied prison in the song I Foni tou Argile (The Voice of the Nargile) by Vangelis Papazoglou, written in the 1930’s.
Five years I’ve been sentenced to the Yedi Kule, / In blackest despair I took to smoking the hash pipe (nargile), / Blow, suck, pull some off, press it in, light it up…/ Keep an eye out for the Vlachs, the yokel guards…(By Vangelis Papazoglou, early 1930s – translated by J. Leonard).
Another reference is in the song Sto Yedi Kule (Gia Mia Gynaika Hathika) – In the Yedi Kule (For A Woman I Was Lost):
If you want to see, Mama, your misfortunate child, / Come inside the Yedi Kule, where your soul will weep, / Come inside the Yedi Kule, where your soul will weep, / For the sake of a woman, I was lost, brutally condemned…(Author unknown, translated by J. Leonard).