Until 1970 the building was an ordinary residence. Then the Socialist Party took it over as one of its headquarters, a fitting use on a street that had drawn Santiago's political and cultural life. After the coup of September 11, 1973, the National Intelligence Directorate, the DINA, seized it and turned its rooms into something the neighborhood could not yet name. In the agency's internal code it was called Yucatán. The DINA later tried to erase even the address, changing the brass number from 38 to 40 to confuse anyone who came looking. The deception failed. Today the building is known by the number it wore when the worst happened, a refusal to let the lie stand.

Roughly 1,100 people passed through these rooms. They were overwhelmingly young: of those killed, 38 were under 25, and a dozen were minors not yet 20. They were students, organizers, and members of the Revolutionary Left Movement, the Socialist Party, and the Communist Party, though some held no party card at all. Ninety-four people were executed or disappeared after being held here, among them 13 women, two of whom were pregnant. To strip these numbers back to their human weight: these were sons and daughters in their twenties, taken from a city going about its business, their families left to spend decades not knowing where the bodies had gone. Forty-seven of them are counted among the 119 victims of Operation Colombo, a regime scheme that planted false stories abroad claiming the disappeared had killed one another in exile.

Blindfolded and unable to see the city, the prisoners learned the building through sound. They heard church bells nearby and could not tell which church it was, so they named the place themselves. Some called it the House of Bells. Others, with the bleak humor that survives in terrible places, called it the Palace of Laughter, or simply La Silla, The Chair. The bells came from the Iglesia de San Francisco a few blocks away, one of the oldest churches in Chile, ringing over a torture house as it had rung over the city for centuries. The detainees could not name their prison, but they could mark time by those bells, and through their later testimony to the Rettig and Valech commissions, they gave the rest of us a way to hear it too.

By the end of 1974 the DINA had built larger facilities at José Domingo Cañas and Villa Grimaldi, and Londres 38 was closed, its prisoners scattered. The building passed through other hands, the number quietly altered, the street resuming its pretty calm. But survivors and the families of the disappeared did not let it disappear in turn. In 2005 the house was declared a national monument, and in 2010 a collective won the right to run it as a space of memory. It is open to the public now, kept deliberately bare: empty rooms, a few traces, the names. The emptiness is the exhibit. Standing inside, you are asked not to look at artifacts but to imagine the people, and to understand that the most unremarkable door on a beautiful street once hid the beginning of a machine built to make human beings vanish.