
The first line on Madrid’s underground railway network, the Metro de Madrid, was inaugurated on the 17th October 1919 by King Alfonso XIII. It had eight stations along 3.3 kilometres of track. Ever since that date the Metro has experienced progressive growth, which has made access possible to the majority of the capital's districts and to some of the most important municipalities in the metropolitan area. Today it is the sixth longest metro system in the world, with 300 stations and 292 kilometres of track, 90 percent of it underground.