An archaeology of collapse
The ruins of São Miguel das Missões are the most prominent remnant of a unique 150-year social and architectural experiment. Beginning in the early 17th century, Jesuit missionaries established 30 self-sufficient towns, called "reductions," for the Guaraní people in the borderlands of present-day Brazil, Argentina, and Paraguay. At their peak in 1732, these missions housed over 141,000 Guaraní who sought protection from Portuguese slave traders, known as bandeirantes.
The archaeological record shows a highly organized society. Each town centered on a large plaza, dominated by a stone church. The Guaraní lived in long, single-story stone apartment blocks, with individual family units opening onto large verandas supported by columns—an architectural adaptation to the Guaraní preference for spending time outdoors. The most famous of the surviving churches, São Miguel Arcanjo, was built by Guaraní laborers over ten years, from 1735 to 1745, using local red sandstone. Its design, attributed to Italian Jesuit architect Giovanni Battista Primoli, is a distinct style now called Guaraní Baroque, combining European designs with indigenous materials and motifs. Surviving foundations reveal workshops, gardens, and carefully planned infrastructure.