Eptapyrgio, the fortification on the Acropolis of Thessaloniki, was built in the early 14th century and has dominated since as the highest point of the city. It has ten towers and mezzanine towers, to supervise the area, the accommodation of the troops, and its function as a shelter in case of occupation of the city. Built on the site of an older fortification, during the reign of the Palaiologon, it is located at the southeastern end of the walls of Thessaloniki, in Upper Town.
After the conquest of Thessaloniki by the Ottomans, in 1430, the middle tower was erected and given the name "Genti Koule", by which the fortress complex is known. The phrase is rendered in Turkish as "Seven Towers", while in Istanbul there was a similar building called "Genti Koule", known as one of the cruelest prisons. Eptapyrgio underwent structural changes during the Ottoman period and especially at the end of the 19th century, when it was turned into a prison, with the addition of buildings, cells, and functional spaces. With the liberation of Thessaloniki, it maintained its function as a prison, until 1989, when it was closed and returned as a monument to the Ministry of Culture. Today it is visitable, ready to tell its story to visitors, of the people who passed through its walls and especially those who lived in its humid cells.