Eighty years after the start of the Spanish Civil War, the country is trying to recover and identify the remains of people who were forcibly 'disappeared'. It is estimated that over 100,000 men and women were executed and buried in unmarked graves during the conflict. It is thought there may be more than 2,000 mass burial sites across Spain dating from the 1936 to 1939 civil war and the ensuing dictatorship of General Francisco Franco. Only a handful have been dug up.

Spanish Civil War graves
Aida Rodriguez, biologist member of the Association for the Recovery of Historical Memory of Valladolid, uncovers human remains in one of the three mass gravesJuan Medina/Reuters

In the central Spanish city of Valladolid, the council has authorised and paid for excavation work to start uncovering graves that archaeologists believe conceal more than 1,000 unidentified bodies. Since April, workers have emptied three graves of 185 bodies that will be sent to a forensic archaeologist for analysis in the hope it may help to identify the dead.

"This is a question of national dignity and human rights rather than opening the wounds of the past," says the mayor of Valladolid, Oscar Puente, whose council paid €25,000 (around £22,000) to employ a professional team to work on the site. "We could not simply look away."

Spanish Civil War graves
The remains of bodies are seen during the exhumation of the one of the three mass graves that contain in total the remains of around 200 bodies believed to have been killed by Spain's late dictator Francisco Franco's forces during the Spanish Civil WarJuan Medina/Reuters
Spanish Civil War graves
A member of the Association for the Recovery of Historical Memory of Valladolid removes a bullet from a human skullJuan Medina/Reuters
Spanish Civil War graves
Gonzalo Saiz, archaeologist member of the Association for the Recovery of Historical Memory, recovers a human skull found in a mass graveJuan Medina/Reuters
Spanish Civil War graves
Julio del Olmo, archaeologist member of the Association for the Recovery of Historical Memory of Valladolid, exhumes remains from one of the mass gravesJuan Medina/Reuters

They have started examining the area with radar pulses to find more unmarked mass burial sites. As many as 10 pits filled with bodies could be in the graveyard, says Julio del Olmo, the archaeologist overseeing the dig. They victims had been executed following judgment in kangaroo courts, or slain in small groups and tipped into the pit by truck, he said.

Archaeologists brush soil away from skeletons, some wearing decayed leather boots. The bodies are interspersed with crumbly white soil, the quicklime that was spread on the recently executed to prevent smells and prevent disease. Even so, slaughter on such a grand scale must have reeked, says del Olmo.

Spanish Civil War graves
A skeleton, still wearing shoes, lies in one of the mass gravesJuan Medina/Reuters
Spanish Civil War graves
A member of the Association for the Recovery of Historical Memory of Valladolid holds a shoe found in one of the three mass gravesJuan Medina/Reuters

Abilio Perez, an octogenarian former bar owner, tended the unmarked area above the graves alongside his wife for six decades, leaving flowers on All Saints' Day and marking off the area with four iron rods and chains. A priest told a relative that the bodies of his wife's father and brother were dumped there after being executed by Franco's forces in the autumn of 1936. He was told for years by authorities that nothing was there. "We put a cross there, but it was taken away," he said.

Spanish Civil War graves
Abilio Perez stands in front of the mass grave which he and his wife have been tending for six decades and where he believes his father in law was thrownJuan Medina/Reuters
Spanish Civil War graves
Abilio Perez holds a family picture close to the mass grave where he believes his father in law was thrown after being killed by Franco's forcesJuan Medina/Reuters

Spain, in common with many Latin American countries in their transition to democracy, passed an amnesty law in 1977 which pardoned the crimes of the Franco government. The mass graves were left undisturbed. However, there is increasing interest from a new generation to face up to the country's past.

The opening of graves and acknowledgement of their existence symbolise a positive change on behalf of Spanish institutions, says del Olmo. But it is too late for most of the relatives who remember the executed men and women. "It's unforgivable that this is being done now and not then," he said, taking a break from preparing a skeleton to be photographed.

"Just 25 years ago the widows, who suffered the most from this loss, were alive. Now they're all dead. The only children alive are the youngest. That is something to which all the governments of this country have been impervious," he said.

Spanish Civil War graves
A human skull is seen inside one of the three mass graves at El Carmen cemetery in ValladolidJuan Medina/Reuters
Spanish Civil War graves
Human remains are collected during the exhumation of the one of the three mass graves that are thought to contain around 200 bodiesJuan Medina/Reuters
Spanish Civil War graves
Boxes containing human remains are piled in a garage after being dug out from the three mass gravesJuan Medina/Reuters
Spanish Civil War graves
An execution order is shown in the official registry in Valladolid provinceJuan Medina/Reuters

Historians estimate as many as 500,000 combatants and civilians were killed on the Republican and Nationalist sides in the war. Atrocities were committed on both sides. The victors under Franco executed thousands more after the war, according to British historian Paul Preston's book "The Spanish Holocaust".