In less than a minute on a summer evening in 1944, an earthquake reduced the city of San Juan to rubble, leaving ten thousand dead and half the province homeless. The worst natural disaster in Argentine history, the tragedy was an indictment of the old political order and a spur for the new order to come.On June 4, 1943, a military coup overthrew the last of the fraudulently elected democratic governments that had ruled Argentina since 1930. The military denounced not only the deposed regime but the liberal democratic order itself as fundamentally unjust and corrupt, proclaiming a need for social justice under authoritarian rule. Here the recently-installed military regime had its first chance to deliver on promises of social justice, as the little-known secretary of labor, Colonel Juan Domingo Perón, directed a massive relief campaign and commissioned ambitious plans for rebuilding. The social project to build a new citizenship was launched together with the spatial project to build a new city.