National Geographic: America Before Columbus - In spite of its misleading title, this National Geographic video isn't really about America "before Columbus." It is about America _after_ Columbus, specifically the transformation of North America's ecology due to the impact of European settlement.
America wasn't exactly a "New World," but a very old one whose inhabitants had built a vast infrastructure of cities, orchards, canals and causeways. But after Columbus set foot in the Americas, an endless wave of explorers, conquistadors and settlers arrived, and with each of their ships came a Noah's Ark of plants, animals—and disease. In the first 100 years of contact, entire civilizations were wiped out and the landscape was changed forever.
The video's production quality is excellent, with beautiful photography and a introductory story line.