San Ignacio Guazú was the first reduction in what is now Paraguay, founded 1609, and nothing of the mission's fabric survives; what survives is the art. The Museo Diocesano holds thirty polychrome wooden figures carved by Guaraní craftsmen in the seventeenth century, arranged across four thematic rooms — Creation, Redemption, the History of Christ in the Church, and the Society of Jesus — and they are the best single collection of hispano-guaraní baroque sculpture in the country outside Santa María.
The claim the museum makes for itself is that it is a museo vivo: the rooms are still used for classes in painting, singing and woodcarving, so on a weekday you may find the collection sharing its building with children learning to carve. Gs 20.000 gets you in. Ring the mobile before a long drive; the opening hours SENATUR lists for it are contradictory to the point of being unusable — eight different Monday-to-Saturday windows, from 07:00–12:00 to 18:00–00:00, which is a data-entry failure rather than a schedule.