It’s one of the most iconic structures in the United States – the giant granite faces of four American presidents, staring out from the side of Mount Rushmore. But how do you carve faces out of a mountain? Why is the site in South Dakota? What lies hidden behind the faces, buried deep within the rock? Today, investigators are piecing together the true story of Mount Rushmore – and discovering that, one day, the carving of a Native American chief will dwarf even the ‘Shrine to Democracy’. Learn more about your ad choices. Visit megaphone.fm/adchoices