The Thessaloniki Walls (Fortress) are the result of a long building process and continuous maintenance, that dates back in the foundation of the city from Cassander (316 BC) till the beginning of the 20th century, and have saved the city many timew from the external enemy. The main construction phases were undertaken during the 3rd, 4th and 5th century AD, while the parts that have been better preserved belong to the Byzantine period, particularly the time of the Emperor Theodosius (4th century AD). Overall, of the 8,000m of Byzantine walls about 4,300m remain today.
The ancient city walls of Thessaloniki (or Kastra as they are well know among citizens of the city), covered all the uppermost northen side of the city, the Acropolis, and descended the eastern and western sides down to the sea, where they continued along the seafront.
On the west side, where now lies Dimokratias Square (Vardaris district), stood a great gate, the “Golden Gate” of Thessaloniki Walls. Moreover, a small, octagonal tower formed part of the west fortress, whose part of the remains can be seen behind the courthouse. The western walls of the city were mainly constructed from marble benches and architraves from demolished buildings of the ancient city.The Eastern Walls begin from the Tower of Trigonio (“Triangle Tower”), at the edge of the Acropolis, where a well known gate that has been preserved is the “Gate of Anna Palaiologou”. Further down the city center, where Syntrivani Square is today stood the “Cassandrian Gate” and close to the sea was the “Coastal Gate” of Thessaloniki Walls. One of the towers that strengthened the fortrification of the walls was the White Tower.
Between 1873 and 1911 the Turks demolished both the sea walls in order to allow the sea breezes to cool the city, and parts of the western and eastern land walls so as the city to expand beyond its original fortified limits.