These mission ruins are the most complete in Argentina: atmospheric and impressive for the quantity of carved ornamentation still visible and for the amount of restoration. There's a small museum and the ruins themselves feature interactive panels providing multilingual audio (although not all are in operation). Admission includes entry to nearby ruins at Santa Ana and Loreto and to Santa María la Mayor further afield. There's a worthwhile sound-and-light show (foreigners AR$200) at the ruins every nonrainy night.
Founded in 1610 in Brazil, but abandoned after repeated slaver attacks, San Ignacio was established here in 1696 and functioned until the Jesuit expulsion. The ruins, rediscovered in 1897 and restored between 1940 and 1948, are a great example of ‘Guaraní baroque.' At its peak, the settlement had a Guaraní population of nearly 4000.
There are free guided tours (in English and Spanish) of the ruins which leave once a group builds up – usually every half hour or so. You pass between rows of Guaraní houses before arriving at the plaza, on one side of which is the enormous red sandstone church. Impressive in its dimensions, it is the focal point of the settlement. While the red-brown stone picturesquely contrasts with the green grass, the buildings were originally white. Before lime was available, it was obtained by burning snail shells.
Check out the Cotiguazú on the far corner of the site beside the graveyard where widows and women whose husbands had left the mission were secluded along with adulterous females and spent their time spinning wool.
The small museum has panels providing unbiased information (in Spanish with small print English translations to one side) about the missions from both Jesuit and Guaraní perspectives, in addition to some finely detailed wood and stonework found among the ruins. There's a scale model of San Ignacio as it would have been at its peak.
Times for the nightly show vary according to the number of groups. It's a touching, at times haunting, experience played out in various locations using projections onto a mist of water spray, giving a ghost-like quality. Headsets offer a variety of languages.