Guadarrama Tunnel
The Guadarrama Tunnel is a railway tunnel across the Sierra de Guadarrama, along the high-speed route Madrid–Valladolid in Spain.
The tunnel has two tubes. The western tube is 28,407 m long and the eastern tube 28,418 m long, and it is the longest tunnel in Spain. The tunnel was opened for traffic in December 2007. The tunnel is used by the AVE high-speed trains.
