Caseros was conceived by the military governments of the 1960s and took almost twenty years to build, finished in 1979 under the junta of Jorge Rafael Videla. Shaped from above like the letter H, it stacked more than 1,500 cells across twenty-two floors, each cell a concrete box of 1.2 by 2.3 meters fitted with a bunk, a toilet, and a table bolted to the floor. It rose in the middle of an ordinary neighborhood, within blocks of two hospitals, a monument to control disguised as modern penology. When the minister of justice praised its design as the latest science of rehabilitation, he was describing a machine built to deny people the sun.

Roughly 1,500 political prisoners passed through Caseros, most of them left-wing militants and student leaders arrested by the Perón and Isabel Perón governments in the mid-1970s, before the 1976 coup. There is a bitter logic to why many of them survived. Because they had been formally registered with international human rights organizations, they were harder for the regime to simply murder or "disappear," as it was doing to thousands of others beyond the walls during the Dirty War. When a foreign human rights commission visited in 1979, the junta theatrically moved high-profile detainees into the gleaming new Caseros to display how well it treated its prisoners. The building was, in part, a stage set for the world's benefit.

After democracy returned in 1983 and the political prisoners were freed, Caseros filled with ordinary convicts, often five to a cell built for one. The men fought back against their own architecture. In a 1984 riot they tore out toilets and the glass from visiting booths, and they began knocking holes through the outer walls to reach light, air, and one another. Through those holes they invented a small economy of contact. A prisoner would lower a bundle on a rope braided from mattress fibers, and a wife or mother waiting in the street below would catch it, slip in a note or a photograph of a child or a cigarette, and let it be hauled back up. They called these rope-and-bundle lines palomas, pigeons, and on a busy day seven or eight might be flying down to the pavement at once.

Caseros closed in 2001, condemned at last. Demolishing it proved nearly as fraught as building it. A planned implosion was blocked by neighbors who feared the dust, the asbestos, and the rats that might pour from the tunnels beneath, so the tower was instead dismantled by hand, floor by floor from the top down, between 2003 and 2008. During that slow unmaking the artist Seth Wulsin worked across its grid of windows, knocking out panes to form forty-eight ghostly faces that appeared and dissolved along the dying facade, a project he called 16 Tons. By 2008 the central tower was gone. All that remains is the base of its perimeter wall and, beside it, the older Caseros prison, a building first raised in the 1880s, fittingly, as an orphanage.