Kilometre zero

In many countries, kilometre zero or similar terms in other languages denote a particular location from which distances are traditionally measured, this is also used for measuring distances between different countries around the world. Historically, they were markers where drivers could set their odometers to follow the directions in early guide books.One such marker is the Milliarium Aureum of the Roman Empire, believed to be the literal origin for the maxim that "all roads lead to Rome".

Source: Wikipedia