The Appalachian Trail, one of the world's longest continuously marked footpaths, turns 80 this month.

Conservancy and volunteer groups completed the 2,190 mile-long footpath in August 1937 from Maine to Georgia.

The 2,190-mile long trail is a unit of the National Park Service, and passes through 14 states, including Tennessee.

EXPLORE: Appalachian Trail map from the National Park Service

About 3 million people visit the Appalachian Trail each year, while roughly 3,000 people attempt to thru-hike the trail, according to the Appalachian Trail Conservancy.

Only about 25 percent of those who attempt to hike the whole trail succeed.

A.T. Fun Facts from the Appalachian Trail Conservancy:

  • Thousands of volunteers contribute roughly 270,000 hours to the A.T. every year.
  • More than 250 three-sided shelters exist along the Trail.
  • Virginia is home to the most miles of the Trail (about 550), while West Virginia is home to the least (about 4).
  • Maryland and West Virginia are the easiest states to hike; New Hampshire and Maine are the hardest.
  • The total elevation gain of hiking the entire A.T. is equivalent to climbing Mt. Everest 16 times.
  • The A.T. is home to an impressive diversity of plants and animals. Some animals you may see include black bears, moose, porcupines, snakes, woodpeckers, and salamanders. Some plants you may encounter include jack-in-the-pulpit, skunk cabbage, and flame azalea.
  • “Thru-hikers” walk the entire Trail in a continuous journey. “Section-hikers” piece the entire Trail together over years. “Flip-floppers” thru-hike the entire trail in discontinuous sections to avoid crowds or extremes in weather, or to start on easier terrain.
  • Most thru-hikers walk north, starting in Georgia in spring and finishing in Maine in fall, taking an average of 6 months.
  • Hikers usually adopt “trail names” while hiking the Trail. They are often descriptive or humorous. Examples are “Eternal Optimist,” “Thunder Chicken,” and “Crumb-snatcher".