Río Tinto, análogo terrestre de Marte Nature · Minas de Riotinto, Cuenca Minera, Huelva Image of Minas de Riotinto, not of the place itself. The reddish waters of the río Tinto, laden with iron and sulphates through the activity of extremophile bacteria, have made its basin a subject of astrobiological study as a terrestrial analogue for Mars. Photo: hombre_invisible (CC BY-SA 4.0) What to see and do in Minas de Riotinto