The Appalachian Trail (AT) is considered to have been established in 1921 when Benton MacKaye proposed a series of outdoor encampments linked by one trail. The 2,168-mile (3489.2 kilometers) trail begins in Maine and ends in Georgia. Hikers can choose to hike the whole trail, or simply go on a day hike or backpacking trip by starting at one of the AT's numerous trail heads. A popular trip is to Clingman's Dome, one of the highest peaks in the Great Smoky Mountains National Park, which rises 6,643 feet (2024 meters) and is located along the state-line ridge of North Carolina and Tennessee.