The origin of balneology in the region is associated with oil exploration efforts that began about 60 years ago. Deep wells, like the ones at Gaspar, Belén, Arapey, Artigas, Daymán, Guaviyú, Almirón, Paso Ulliestie were drilled in the Uruguayan sector of the Chaco-Paraná Basin. Some of them brought about the development of thermal spas (“Centros Termales” in Spanish) that are still in operation