Avenida General Paz (official name Ruta Nacional A001 - National Route A001) is a beltway freeway surrounding the city of Buenos Aires. Roughly following the boundary between the city and Buenos Aires Province, it is one of the few motorways in Argentina that is toll-free. It carries three lanes of traffic in each direction during most of its length, and five lanes between the Pan-American Highway and the Río de la Plata. There are feeder roads in both directions and there are service areas along its length, usually with a gas station and fast food restaurants. The route was the first highway in Argentina, built between 1937 and 1941 with a cost of m$n 24 million, and officially inaugurated on July 5, 1941. From Wikipedia
