The Valley of Cuelgamuros, formerly known as Valley of the Fallen , is a monument in the Sierra de Guadarrama, near Madrid. The valley contains a Catholic basilica and a monumental memorial in the municipality of San Lorenzo de El Escorial. Dictator Francisco Franco ordered the construction of the monumental site in 1940; it was built from 1940 to 1958, and opened in 1959. Franco said that the monument was intended as a "national act of atonement" and reconciliation.

The Sierra de Guadarrama is a mountain range forming the main eastern section of the Sistema Central, the system of mountain ranges along the centre of the Iberian Peninsula. It is located between the systems Sierra de Gredos in the province of Ávila, and Sierra de Ayllón in the province of Guadalajara.