After months of work, on the 17th of October 1919, the project designed by engineers Carlos Mendoza, Miguel Otamendi and Antonio González Echarte for the construction of a commuter rail in the city of Madrid was ready for opening.
That day the king of Spain Alfonso XIII officially inaugurated the first Metro line between Puerta del Sol and Cuatro Caminos. This ground connection had a total length of 3.48 km and eight stations: Cuatro Caminos, Ríos Rosas, Martinez Campos, Chamberí, Bilbao, Hospicio, Red de San Luis and Puerta del Sol.
The tunnels for this new transport started in Glorieta de Cuatro Caminos, and ran under the streets of Santa Engracia, Luchana, Fuencarral and Montera in direction to Puerta del Sol.
The trains carried the route in ten minutes, which meant a significant reduction compared to others types of transportation at the time. After ten days, on October 31st was opened to the general public.
Metro was a great success with locals and in only one year had more than 14 million of passengers