The terror had a bureaucratic name: the National Reorganization Process, the self-styled label of the military junta that seized power in Argentina in 1976. In the period that came to be known as the Dirty War, the state kidnapped, tortured, and murdered thousands of its own citizens, holding them with no charges and no trial. The official justification was a war against subversion and terrorism. The reality was that most of those who disappeared were social activists, political dissidents, or simply the relatives, friends, and acquaintances of anyone the regime deemed ideologically suspect. They were teachers, students, workers, organizers, ordinary people swept up and made to vanish. The word for them entered the language: los desaparecidos, the disappeared.

On paper, the building was the headquarters of the provincial police and the home of an intelligence unit, the Servicio de Informaciones of Regional Unit II. In practice, between 1976 and 1979, it was a place where people were held in secret and tortured. The man in charge of the intelligence service, a Gendarmería commander named Agustín Feced, did not confine himself to giving orders; he took part personally in kidnappings, in torture sessions, in executions. Prisoners bitterly nicknamed the site El Pozo and La Favela. Decades later, the courts would catch up. The investigations into Feced and his collaborators, opened in 2004, became one of the central cases in Argentina's long reckoning with the crimes of the dictatorship.

Democracy returned to Argentina in 1983, but the building kept doing its official police work for nearly two more decades, as if nothing had happened inside it. That changed in 2001, when human rights organizations demanded that the place be preserved rather than quietly used and forgotten. The provincial government agreed. The police facilities were dismantled and moved elsewhere. Part of the building passed to municipal control, part became a provincial government office, and the central courtyard was opened as a public square. In 2002 the most significant sections, the rooms where people had been held, were granted to a coalition of human rights groups under the name Centro Popular de la Memoria. The Pit had been taken back.

What makes this memorial different is who tends it. The Center is managed by the relatives of victims of forced disappearance, the mothers and grandmothers and children of the people who never came home. They have turned the site into an exhibition of remembrance, hanging newspaper clippings and photographs, the same images of the disappeared that families have carried in demonstrations for half a century, each face a demand that someone account for what happened. A documentary film traces the investigation and recovery of the site and gathers the testimony of survivors and the researchers who pieced the history back together. Standing in the underground rooms, the visitor is left with the plain fact the families insist upon: these were real people, and they are not forgotten.