Kilometre zero
In many countries, Kilometre Zero (also written km 0) or similar terms in other languages (also known as Zero mile marker, control stations or control points) is a particular location (often in the nation's capital city), from which distances are traditionally measured. They were markers where drivers could set their odometers to follow directions in early guide books.
A similar notion also exists for individual roads (that is, all locations on the road have a number, depending on their distance from that location), and for individual cities (often the city's central post office is used for this).
The most famous such marker of which any part survives from ancient times is the Milliarium Aureum ("Golden Milestone") of the Roman Empire, believed to be the literal origin for the maxim that "all roads lead to Rome".
Countries
Argentina
Argentina marks Kilometre Zero with a monolith in Plaza Congreso in Buenos Aires. The work of the brothers Máximo and José Fioravanti, the structure was placed on the north side of Plaza Lorea on October 2, 1935; it was moved to its present location on May 18, 1944. An image of Our Lady of Luján (honored on the monolith as "the patron saint of the national road network") appears on the monolith's north face, a relief map of Argentina is on the south face, plaques in honor of José de San Martín are west, and on its eastern side, the date of the decree and the name of the relevant authorities.
