A kilometer point or PK is a landmark of a route from the zero point of a road, railway or waterway. The starting point is called PK0.
For the road, the kilometer point is a particular point in a country or a city from which road distances are counted and makes it possible to locate the road at a given geographical point of the road from its PK 0.
The PK number is an essential element for all interventions by road network maintenance agents but also local authorities such as the police, gendarmerie, firefighters and other emergency services.
In Algiers, the first PK0 of Algeria was located at Haut Mustapha (current Hydra) in Algiers, currently Voirol Colonne named after the one who in 1834 created from this point the opening of the road to Birmandreis, this road, from barely three kilometers, appears to be a very modest achievement, except that it is the beginning of the Imperial road which leads to Chad, more than 4000 kilometers away. General Voirol (1781-1853) oversaw the construction of the first roads in Algiers as well as numerous military works. In this place, a marble stele was built (which no longer exists) and of which the tomb of General Voirol (located in the "Champs-Bruley" cemetery in Besançon, France) happens to be a replica of this stele. .
The PK0 of Algiers was moved after independence to the square in front of the Grande Poste of Algiers Center. A plaque identifying it has just been affixed.