Milion, Landmark in Istanbul
The Milion was a monument erected in the early 4th century AD in Constantinople.
It represented the starting point of the Byzantine measurement for distances for all the roads leading to the cities of the Byzantine Empire.
The historical monument gives insight into the Byzantine Empire's span of control and measurement system.
Today, it's located close to the Hagia Sophia.
Milion, though partially destroyed, still represents the symbolic 'kilometer zero' for Turkey.
Sources: Wikimedia, OpenStreetMap