But many Americans might not know the secret behind one of the country's most iconic political monuments. Enter: The Hall of Records at Mount Rushmore. Where the frontal lobe of Abraham Lincoln's ...

Today the first question out of many visitors’ mouths is not why, or even how, Mount Rushmore ... that runs behind the presidential heads—an oblong sliver, looking like the secret entrance ...

Around then, the South Dakota historian behind the Mount Rushmore initiative approached Borglum—an overture that enraged Borglum’s Atlanta backers, who fired him on February 25, 1925.