It is an archaeological park in Santa Fe, located 1 kilometre away from the locality of Cayastá and 76 kilometres from the capital of the province. Its entrance is on Provincial Route 1.
It is the place where the first city of Santa Fe was founded by Juan de Garay in 1573, which later moved to its present location around 1660. Nowadays, there are remains of what used to be the Plaza de Armas (the main square), houses and churches. As you walk around it, you can see sheds, which have structures inside that have been rescued and restored. Some of them are closed and others are open to see inside (consult with those who coordinate the park).
As for the churches, of the six that existed, only the ruins of three remain. One of them, the church of San Francisco, can be visited and inside you can see replicas of skeletons (the originals were removed to preserve them in an enclosure with restricted access that is in another part of the park) because at that time these temples also served as cemeteries. In this same church is the compartment where the remains of Hernandarias (the first American-born governor of the Río de la Plata and Paraguay) and his wife Doña Jerónima (daughter of Juan de Garay) were found.
In another sector of the park you can visit the Casa Ambientada, which is a replica of a large house. And near the entrance of the park there is a site museum that exhibits original pieces rescued from the excavations, as well as a large scale mock-up that represents what the city was like in those times.