Filmmaker Kevin Gallagher walked the 2,178-mile  length of the A.T., and each day, he took photographs of a single quintessential section of the trail. Twenty four successive steps down the trail were captured each day. At the end of his six-month journey, he had over 4,000 slides, which he pieced together to offer a condensed view of an Appalachian Trail thru-hike. After this armchair adventure, you’ll understand why the A.T. is often called The Green Tunnel. Click here for a five-minute thru-hike.