Spain's blood-red Río Tinto may hold clues to life on Mars, Nasa says

PC: David Santiago Garcia/Aurora Photos/Getty Images At first glance, the Río Tinto in southwestern Spain looks almost unreal. For around 50 kilometres, the water flows in shades of deep red and orange that seem more fitting for an artist's palette than a natural river. Yet its extraordinary appearance is not the result of artificial dyes or recent contamination. It reflects a landscape shaped by ancient geology, microscopic organisms and thousands of years of mining. What appears to be an environment too harsh to support life has instead become home to specialised microbes that thrive where most living things cannot. According to Nasa, those unusual conditions make the Río Tinto one of the closest natural environments on Earth to parts of Mars, giving scientists a rare opportunity to test how they might one day detect life beyond our planet.Why Spain's Río Tinto river is naturally blood red and as acidic as vinegarThe Río Tinto, whose name translates as "stained river", cuts through one of Europe's richest volcanic sulfide ore regions. These mineral deposits formed hundreds of millions of years ago when volcanic activity dominated what is now southern Spain.As groundwater and oxyg...