The first railroad line departing from Madrid (the second in Spain and the third in the Iberian Peninsula) was built in 1851 between Madrid and Aranjuez. Soon the growing Spanish railway system was dominated by two large companies: the "Compañía del Norte" (Northern Company), who operated the lines between Madrid and the Atlantic North of Spain from the "Estación del Norte" (now Príncipe Pío),and the Madrid-Zaragoza-Alicante (MZA) who operated the lines between the capital and the Mediterranean and Andalusian cities from the Atocha station. Another station, Delicias, served the line to Lisbon. Other smaller companies operated from Madrid, mostly in narrow gauge. After the Civil War, in 1941, the ailing railway companies were nationalised and joined in the new RENFE, and the narrow gauge lines were progressively closed, the last one in 1970. Almost at the same time, the new Chamartín station was built and all services were transferred to the main stations: Chamartín for the north and east-bound and the international services and Atocha for the south and west-bound trains. Both stations were linked by a tunnel, the Connection Railway Line ("Línea de Enlaces Ferroviarios", a line to link the MZA lines with the Norte lines; the building started during the Second Republic and was only finished in 1967. The delays gave the tunnel the nickname of "Túnel de la risa" (funny tunnel), after a fair attraction very popular in the 1930s.