Santa María de Fe is a village of red earth streets around an enormous grass plaza, laid out by the Jesuits in 1647 and never really changed. It is 25 km off Ruta 1 from San Ignacio, and almost nobody comes.
The Museo de Arte Jesuítico occupies three bays of the surviving row of indigenous houses on the plaza. Inside are around fifty polychrome wooden figures carved by Guaraní sculptors in the 17th and 18th centuries — a Nativity, apostles, angels, a much-loved set of the Annunciation — and they are, by a distance, the finest carvings on public view in Paraguay. The room is small, the lighting is daylight, and you will most likely be alone in it.
There are black howler monkeys living in the trees on the plaza. They are wild, they are loud at dawn, and they are the first thing everyone mentions afterwards.
The village also has a long association with the Santa María Education Fund, a British-founded charity running schools and a hotel whose profits go into them, which is where most visitors stay. Combine it with San Ignacio Guazú and Santa Rosa in a day if you have a car; on buses, give it a night.