The United States’ National Mall is an urban park unlike any other in the world, a landscape that seems so timeless and eternal it’s easy for visitors to forget that it is actually man-made. Now, for the first time, a National Geographic/PBS Special will bring the surprising story of the Mall’s creation and evolution to a national audience. Using a mixture of contemporary and archival footage, state-of-the-art graphics and exclusive aerials shot within highly restricted airspace, this hour will trace the Mall’s — and the country’s — transformation from fields and farmland to national icon.