Today, Spain presents a modern front. It is a key member of the European Union and a diversified economy with a vibrant start-up scene. It boasts the longest high-speed rail network in Europe and accelerating progress in women's and LGBTQ rights. So it's easy to forget that less than 50 years ago, the country was run by a military dictator who was a fascist ally of Adolph Hitler.

To make it even easier to forget, the Spanish parliament passed "La Ley De Olvido," or "The Law of Forgetting," when the dictator Francisco Franco died in 1975. A blanket amnesty law, it gave immunity to members of Franco's regime who had participated in crimes and caused mass suffering, in the hope that it would help ease the transition to democracy.

But as human rights lawyer Maite Parejo of The Guernica Group told CBS News, "Victims are not forgetting. It's the other way around." The relentless work of survivors of Franco's regime is forcing Spain into a long overdue reckoning with its past, uncovering some truly horrifying stories.

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Few as bizarre and dystopic as the story of Spain's stolen babies, explored in the "Down To Earth" documentary. In it, CBS News correspondent Jim Axelrod speaks with family members who say that for decades, Franco's people kidnapped newborn babies from maternity wards, targeting the families of leftist opponents of the regime and giving the infants to political supporters. The kidnappings eventually expanded to take the children of the poor and vulnerable in general. Some lawyers believe as many as several thousand babies may have been stolen.

But family members did not forget their lost sons, daughters, brothers and sisters. Groups such as Soledad Luque's Todos Los Niños Robados Son También Mis Niños ("All stolen children are also my children") have persistently advocated for justice in the face of mass indifference. Luque's group has been working exclusively with lawyer Maite Parejo and professors, such as Aránzazu Borrachero Mendívil and Pedro Lange Churion. Mendívil has diligently compiled numerous testimonies, creating Mujer Y Memoria (Stolen Motherhoods) — a web archive full of documentation, video testimony, and heartbreaking photographs taken by Pedro Lange Churion, which were shown in an exhibition in March 2019 in Valencia at the Carmen Cultural Center. Their images and videos are also featured throughout the "Down To Earth" documentary, "Stolen Babies."

The result of their efforts is a paradigm shift in international law. In 2010, an Argentine court under the oversight of Judge Servini de Cubria agreed to take on investigating and prosecuting all of Franco's crimes (stolen babies, torture, executions, exile and unmarked graves). It's a neat reversal. In 2005, Spain's courts themselves used the jurisdiction granted by international human rights law to try crimes committed by Argentina's military dictatorship. It led to the collapse of Argentina's own amnesty law that was passed in 1987, and finally led to prosecutions.

Now, Argentinian lawyers say they are returning the favor, hoping the publicity generated by their trial will lead to pressure on Spain's courts and parliament to overturn the "Law of Forgetting." In the meantime, the haunting story of Spain's stolen babies serves to remind us that even countries which seem ostensibly modern today often have a harsher underbelly when you look beneath the surface.