This research project documents the long-term economic impact of the Guarani Jesuit Missions in South America. It does so by combining data from historical Archives and municipal level Census data from Argentina, Brazil and Paraguay. Missions resulted in higher levels of income and educational attainment today. Results are robust to the inclusion of geographic controls and the usage of instrumental variables to proxy for missionary distance. Using intermediate historical censuses, human capital appears consistently higher closer to missionary districts. This persistence of educational transmission is consistent with cultural explanations, such as native assimilation and the persistence of occupational activities. Additional tests suggest that migration and tourism are not driving the results, and that the impact is specific to missions from the Jesuit (as opposed to the Franciscan) order.