Great Smoky Mountains National Park lures more than 9 million visitors a year to an 800,000-acre swath of rich, and dense, southern Appalachian forest. Keeping trails open, fulfilling all needs, and coping with all those visitors, is a heady challenge for the National Park Service. And that's where Friends of the Smokies fills a mighty role. In this installment of the Traveler's Essential Friends project, we introduce you to the Foundation and its mission in the park