 The Guaraní were the first inhabitants of the islands.They built embankments of sand and earth as look-outs and flood defences known as "cerritos", which can still be seen rising above the dense vegetation which characterises the river delta.It is thought that the Guaraní arrived in Ibicuy in search of the "tierra sin mal", the earthly paradise inhabited by the spirit Ñandey, located in the east close to the sea.