Discover a completely different area to the rest of the world, so much so that NASA has set a base to study this mysterious land. Rio Tinto and its surroundings have been exploited for its copper, silver and gold content for more than 2000 years which changed the landscape of this area so much that it now resembles Mars. The main river here runs among the old mining fields, transporting the minerals of the soil. These metallic minerals turn the river into a reddish color with acidic waters, making life in the river nearly impossible.  From Seville, visit the biosphere reserve of Dehases de Sierra Morena. The reserve offers you the chance to see some of the bulls and Iberian pigs which inhabit the area. Continue to the town of Aracena, where you can visit the castle and the Gruta de las Maravillas, literally "Cave of Wonders." Visit the Peña de Arias Montano, where you will explore the Mediterranean forest revealing in the stunning environment. Discover the Mosque of Almonaster la Real, the Rio Tinto as well the a forest full of chestnut trees. The tour also offers the possibility of visiting a farm of wild bulls. After Rio Tinto, head to Aracena, a small town located in the middle of Sierra Morena. This is the capital city of the Natural Park Sierra de Aracena and Picos de Aroche. Aracena offers visitors amazing trails through its Dehesas full of cork trees and oaks, where the Iberian pigs live in freedom and peace. Once in Aracena, you will visit Grutas de las Maravillas, a natural cave almost 2000 meters long, full of stalactites and stalagmites formed by the water running in the limestone.