Megalithic Walls of Altamura

The Megalithic Walls of Altamura (Italian: Mura megalitiche di Altamura) are defensive walls dating back to the 4th century BCE. They were the city walls of the ancient city of Altamura, Italy. Nowadays, only a few parts of the original wall remain; the original track of the wall spanned over a length of about 3.6 km.

Source: Wikipedia — Megalithic Walls of Altamura (CC BY-SA 4.0)