Having carried out the National Plans for Industrial Heritage, Preventive Conservation, Cultural Research, and the Cultural Landscape (Planes Nacionales de Patrimonio Industrial, Conservación Preventiva, Investigación Cultural y Paisaje Cultural) the Spanish Cultural Heritage Institute (IPCE), under the auspices of the Ministry of Culture, began the implementation of a National Plan for the Conservation of 20th-Century Heritage (Plan Nacional de Conservación del Patrimonio Cultural del Siglo XX). In the area of architecture, the IPCE commissioned the Iberian DOCOMOMO Foundation to draft the initial list of buildings to be included in the plan.
The foundation carried out this work from 2011 to 2013 through its Technical Commission and a Commission of Experts. A list was drafted of the 256 most significant buildings from the period 1925-1965 for inclusion in the National Plan for the Conservation of 20th-Century Heritage, and documentation was compiled on the 256 selected elements.
Following this phase, in 2017 and 2018 the selection focused on the period between 1965 and 1975, resulting in a list of the 153 most significant buildings from that time frame, for their integration into the heritage plan.