The monument, a landmark of 20th-century Spanish architecture, was designed by Pedro Muguruza and Diego Méndez on a scale to equal, according to Franco, "the grandeur of the monuments of old, which defy time and memory." Together with the Universidad Laboral de Gijón, it is the most prominent example of the original Spanish Neo-Herrerian style, which was intended to form part of a revival of Juan de Herrera's architecture, exemplified by the royal residence El Escorial. This uniquely Spanish architecture was widely used in public buildings of post-war Spain and is rooted in international classicism as exemplified by Albert Speer or Mussolini's Esposizione Universale Roma.
The monument precinct covers over 3,360 acres (13.6 km2) of Mediterranean woodlands and granite boulders on the Sierra de Guadarrama hills, more than 3,000 feet (910 m) above sea level and includes a basilica, a Benedictine abbey, a guest house, the Valley, and the Juanelos — four cylindrical monoliths dating from the 16th century. The most prominent feature of the monument is the towering 150-metre-high (500 ft) cross erected over a granite outcrop 150 meters over the basilica esplanade and visible from over 20 miles (32 km) away.
Works started in 1940 and took over eighteen years to complete, with the monument being officially inaugurated on April 1, 1959. According to the official ledger, the cost of the construction totalled 1,159 million pesetas, funded through national lottery draws and donations.
The complex is owned and operated by the Patrimonio Nacional, the Spanish governmental heritage agency, and ranked as the third most visited monument of the Patrimonio Nacional in 2009. The Spanish social democrat government closed the complex to visitors at the end of 2009, citing safety reasons connected to restoration on the facade. The decision was controversial, as the closure was attributed by some people to the Historical Memory Law enacted during José Luis Rodríguez Zapatero's premiership, and there were claims that the Benedictine community was being persecuted. The works include the Pietà sculpture prominently featured at the entrance of the crypt, using hammers and heavy machinery. In November 2010, citing safety reasons, the Zapatero government closed down the Basilica for Mass. Mass was celebrated in the open for several weeks. Checkpoints were set up, according to socialist government sources, to prevent right-wing political manifestations such as Falange flags, in accordance with the Historical Memory Law. However, Catholic sources claimed that the government was simply trying to interfere with the celebration of the Mass. After Zapatero's electoral defeat and his leaving office on December 21, 2011, normal service at the Basilica resumed.
In 1999, the Valle de los Caídos was bombed by the Maoist terrorist organization GRAPO.