Delayed, abandoned, and incomplete monuments populated the real and imaginary landscape of South America in the later decades of the twentieth century, turning the built environment into a physical index of political instability and misguided economic policies that I will discuss as a ruin in reverse. Within this landscape, the National Library of the Republic of Argentina stands out because its protracted history contains within it several literary, political, and economic stories. As one of the many ruins in reverse that populate the region, the library brings forth an expanded understanding and chronology for modernity—one directly related to the effects of capital and of a particular transformation of late capitalism that has been called the neoliberal turn. In late twentieth-century South America, dictatorships mobilized modernity's technocratic impulses toward reactionary ends, and economic chaos led to a landscape of ruins. Originally meant as markers of modernity, these buildings became reminders of aspirational pasts that never came to happen. Through their stalled, protracted, or truncated construction periods, these buildings point to other realities revealed by ruination.