The Walls of Thessaloniki
Thessaloniki was first fortified by Cassander when he first founded it in 315 BC. The walls of Thessaloniki as we see them today are the result of construction, extension, and repair work that went on from the fourth century BC to the period of the Ottoman rule.
They were originally 8 km long. Unfortunately only 4 of them survive today...
But still the view is gorgeous!