It was world-famous sculptor Gutzon Borglum's dream to carve sixty-foot-high likenesses of four presidents on a granite cliff in South Dakota. Does that sound like a wacky idea? Many at the time thought so. Borglum faced a lot of opposition and problems at every turn; the blasting and carving carried out through the years of the Great Depression when funding for anything was hard to come by. Yet Mount Rushmore now draws almost three million visitors...