The Spanish Ministry of Defense retains as "secret" 100,000 documents older than half a century which should clarify many dark details of the fascist massacres and other deals in the Civil War and World War II, when fascist Spain was closely allied with Hitler and Mussolini, even if it remained "non-belligerent". Other items of interest could be the relationships of fascist Spain in the Cold War and the dubious aspects of conflicts involving Morocco (Ifni War, West Sahara).
While Carma Chacó, Minister of Defense under Rodríguez Zapatero, seems to have explored the declassification of all these documents, so important for historians and the general public, the initial overture was never approved by the government and the issue remained parked until the neofascist People's Party took power in 2011. Since then nothing has been done about them either.
In addition to these 100,000 documents, there are known hidden blanks in the documentation of the Spanish military available to the public, surely hidden in the High Defense Command. Nobody seems to know exactly how much because, as historians denounce, in Spain there is no information transparency.
According to the law of historical patrimony all documents must be available after 50 years. However the government applies the law of official secrets decreed under fascism, in 1968.
Among the data hidden it is known to be old defense plans, armament projects (possibly hiding the secret nuclear ambitions of fascist Spain), multitude of documents on political repression and censorship, concentration camps, forced work prisoner brigades, summary executions, guerrilla activity, secret deals with other powers, etc. These key historical and political documents are scattered in a number of archives in Madrid, Sevilla, Palma de Mallorca, Ceuta, Barcelona, Las Palmas de Gran Canaria, Cartagena, O Ferrol, Cádiz, etc.
Source: El Mundo[es].