Modern Marvels: Mt. Rushmore.

The incredible tale of how Gutzon Borglum created the world's largest sculpture by carving the faces of four US presidents (George Washington, Thomas Jefferson, Theodore Roosevelt, and Abraham Lincoln) into the Black Hills of South Dakota. The four figures carved in stone pay tribute to the first 150 years of American history. The hour chronicles the "swiveled pointer" that Borglum put in each president's "head", and how workmen hung like spiders 6,000 feet above the ground to blast away 450,000 tons of rock.