A top Spanish investigative judge has launched a criminal investigation into the fate of tens of thousands of people who vanished during the country's civil war and General Francisco Franco' dictatorship.
The BBC's Steve Kingstone in Madrid weighs up the aftershocks of a seismic decision by Judge Baltasar Garzon.
Baltasar Garzon is seen by many in Spain as a polarising figure
Love him or hate him - and few Spaniards are indifferent - Mr Garzon is a genuine superstar.
The 52-year-old investigating magistrate is rarely out of the news: in a glittering judicial career, he has pursued Eta, al-Qaeda, and alleged human rights abusers in South America - most famously, Chile's late dictator Augusto Pinochet.
Supporters see him as a fearless crusader; critics portray the judge as an egotist, who craves media attention.
But now, this polarising figure has embarked on the most contentious crusade of all by, in effect, sitting in judgement on the regime of Gen Franco, who ruled Spain for almost four decades until his death in 1975.
The principal allegation is that Gen Franco, together with 34 senior aides, oversaw a systematic campaign to eliminate their left-wing opponents. Mr Garzon characterises this as a "crime against humanity".
In an exhaustive 68-page edict, the judge refers to 114,000 alleged victims who "disappeared" over a 15-year period, following Gen Franco's military uprising against the elected Second Republic government in July 1936.
Many are said to have been summarily executed during the brutal civil war, which Franco's Nationalist forces won in March 1939; others were murdered later, as the general consolidated his power.
"The fight against this scar, this impunity will never cease," Mr Garzon told me at a recent book launch - speaking in general terms about crimes against humanity.
"And if we're referring to the investigations in Spain about past eras, then justice must follow its course."
Many seasoned academics share Mr Garzon's historical perspective, and some go even further in their choice of language.
"It was virtually genocide," says the Madrid-based historian Ian Gibson.
"It came from the top, it was systematic, and they had planned it before the war began. Documents exist showing that, if the coup failed, they would set in motion this policy of extermination," Mr Gibson says.
'End to silence'
The most immediate effect of Mr Garzon's dramatic intervention will be the opening of 19 mass graves, believed to contain the remains of missing victims.
Mr Garzon accused Gen Franco's regime of crimes against humanity
Such excavations are not new in Spain, but until now they have been organised on an ad hoc basis, by relatives of the dead and volunteer archaeologists.
"For many people, the intervention of Garzon means an end to silence and fear," explains Emilio Silva, who unearthed the remains of his grandfather eight years ago, and today runs the Association for the Recovery of Historic Memory.
"Many families are now contacting us for the first time... some are sending information about killers who are still alive today. This is not a political question anymore - we're talking about justice," Mr Silva says.
The prospect of elderly men - now well into their 90s and above - facing prosecution is, for the first time, conceivable.
Spain's interior ministry has said it will co-operate with a request from Mr Garzon to supply details of any surviving senior members of the Spanish Fascist Party (Falange) who are alleged to have carried out summary executions in Gen Franco's name.
Unsurprisingly, Mr Garzon's actions have unleashed an almighty storm from opponents who accuse him of playing God.
Survivors of the civil war Falange movement may now face prosecution
"He must be the only Spaniard who hasn't heard that Franco is dead," joked Senator Augustin Conde of the conservative opposition People's Party (PP), lambasting the fact that Mr Garzon had requested documentary proof of the Gen Franco's passing.
Manuel Fraga, the PP's 85-year-old founder and a former minister under Gen Franco, called the ruling "nonsense, a very serious mistake"; while the right-leaning El Mundo newspaper fumed that Mr Garzon was "neither morally nor mentally capable of judging anyone".
Intriguingly, Spanish state prosecutors are among the dissenters, and have appealed against Mr Garzon's right to address the historical controversy.
They argue that his intervention violates the 1977 Amnesty Law, which pardoned politically-motivated crimes by Gen Franco's friends and foes alike. By guaranteeing that the past would not be raked over, the law underpinned Spain's delicate transition from dictatorship to democracy.
Others have more personal reasons for opposing the judge - notably the family of the Francoists' most famous victim, the celebrated poet Federico Garcia Lorca, who was murdered in August 1936.
Together with thousands of other victims, his remains are thought to be buried in the southern province of Granada, at a site which Mr Garzon has ordered excavated.
"We don't think finding the remains would add anything to his already well-known biography," explains Laura Lorca, the poet's niece.
"We should not disturb the dead... and his fame should serve to protect that place," she says.
The Lorca family also has practical concerns about a potential exhumation of victims.
"It would be very difficult to avoid it being turned into a media spectacle," says Laura, "there are a lot of people who would be after the image of those remains."
But relatives of other victims disagree, arguing that Mr Garzon is simply displaying the same rigour towards domestic history which Spanish judges have shown in international human rights cases, under the principle of "universal justice".
"People should pay for their crimes," says Mr Silva. "It's the same whether it's in Spain, Argentina, Chile or Serbia. Spain shouldn't be different."