Lau Haizetara Gogoan (meaning recalling to the four winds, i.e. speaking out loud) has arrived to the conclusion that the Fascist genocide in the Basque Country was one of the most brutal in the Western World in the 20th century. In the case of Navarre, it murdered 1.13% of all people, a situation only superated by Bosnia of all studied cases. Even the raw numbers approach those of fascist Argentina (which has a population many times larger).
They protest that, while in other cases of brutal fascist repression and genocide, truth comitees have been created to clarify what happened and compensate as much as possible the victims, in Spain nothing of the like has ever happened. Instead the matter is once and again hidden under the rug, allowing the modern fascists of the Tory party (now they call themselves "christian-democrats") to attempt once and again to deny it and even to make threats against (the so-called) democracy each time the issue is raised.
Overall it is estimated that some 1 million people (c. 4-5%) were killed during the Civil War and in its aftermath, throught the Spanish state. Most of them did not die in the battlefields. And while the leftists also killed some people, the vast majority of deaths were summary executions in the fascist zone, where anyone who was thought as vaguely "red" was simply murdered without further questions.
This of course did not end with the war. I always remember an anecdote of my aunt (my uncle's wife), who came from Salamanca to work as teacher in Ondarroa (a massively Basque-speaking town, language that she did not know) in the 60s. One of her pupils, a teenager, dared one day to call the Spanish policemen txakurrak ("dogs", our equivalent of English "pigs" in a similar context) . They immediately arrested him and he came out of the police station dead. Just an anecdote, albeit very illustrative of the kind of criminal regime we had to face and we still have to face to a great extent.