Set beside the Río San Javier, these atmospheric ruins are well worth a visit. The river has eroded away a good portion of them and there’s ongoing archaeological excavation, but the most fascinating find by far has been the Iglesia de San Francisco. The Spanish and mestizo inhabitants of old Santa Fe were buried directly beneath the earth-floored church, and nearly 100 graves have been excavated. The skeletons have now been replaced by replicas, but it's still a spooky, atmospheric place.
Graves include those of Hernando Arias de Saavedra (‘Hernandarias’), the first locally born governor of Río de la Plata province, and his wife, Jerónima, daughter of Juan de Garay, who founded Santa Fe and Buenos Aires.
You can also see the remains of two other churches (there were originally six) and the cabildo (town council), as well as a handsome reconstructed period house. Near the site entrance is an attractive museum housing finds, including fine indigenous pottery with parrot and human motifs.
Last entry is strictly one hour before closing.