The Appalachian National Scenic Trail, or simply the AT, is a hiker's Mount Everest. The 2,181-mile trail stretches from Georgia to Maine, and more than 15,000 people have informed the Appalachian Trail Conservancy that they've completed the epic trek. While some people hike the AT in sections over many years, those known as thru-hikers attempt to complete the entire trail in a single season, a commitment that takes five to seven months. The AT is the world's most famous long-distance hiking trail, but many of its hikers are also well-known — some for their trail exploits, others for their inspiring stories of courage and accomplishment. Here's a look at some of the AT'S most famous hikers.

1 of 10 Earl Shaffer National Museum of American History, Behring Center. Earl Shaffer was the first person to walk the AT in one continuous hike, a feat that the Appalachian Trail Conference believed to be impossible. After completing his service during World War II, Shaffer said he wanted to "walk the army out of [his] system," and he began his hike at Mount Oglethorpe, Georgia, on April 4, 1948. There were no guidebooks for the trail, so Shaffer set out with just roadmaps and a compass, and averaging 16.5 miles a day, he reached Mount Katahdin 124 days later. The moment was bittersweet for Shaffer who wrote, "I almost wished that the Trail really was endless, that no one could ever hike its length." In 1965, Shaffer hiked the trail again — this time starting in Maine and hiking to Georgia, making him the first person to complete a thru-hike in both directions. Then in 1998, at the age of 79, he hiked the entire AT again. Believe it or not, there have been older thru-hikers: The record is currently held by Lee Barry who finished his fifth AT hike in 2004 at the age of 81.

2 of 10 Mike Hanson courtesy of Mike Hanson. On March 6, 2010, 45-year-old Mike Hanson set out to hike the Appalachian Trail, and seven months later he completed the more than 2,000-mile trek. What makes his hike so special? He’s completely blind. Hanson spent years testing a special GPS receiver that would guide him to campsites, water sources and other points, and he chose to hike the AT to demonstrate the value of adaptive technology, as well as “the competence and independence of persons with visual impairments.” Hanson says the toughest part of his journey was the mile-long boulder field across the Maine border: “You go over, under, around and between boulders for a mile. If I ever do that again, it will be too soon!”

3 of 10 'Grandma Gatewood' Wikimedia Commons. When Emma Gatewood set out to hike the Appalachian Trail, no woman — and only five men — had ever completed a thru-hike. In 1955, the 67-year-old grandmother of 23 finished the hike and earned herself the nickname "Grandma Gatewood." Upon completion of the epic trail, she told Sports Illustrated, "I would never have started this trip if I had known how tough it was, but I couldn't and wouldn't quit." Gatewood is also known as a pioneer of ultra-light hiking — she hiked the trail in Keds sneakers and often carried just an army blanket, a raincoat and a plastic shower curtain that she used as a bag. "Grandma Gatewood" hiked the AT two more times, in 1960 and in 1963, completing her final hike in sections. She was the first person to hike the trail three times, and she was the oldest woman to thru-hike the trail until Nancy Gowler did so at the age of 71 in 2007.

4 of 10 Bill Bryson Photo: BERTRAND LANGLOIS/AFP via Getty Images The image of an average AT hiker is likely one of a young, fit outdoorsy type, but travel writer Bill Bryson sought to change all that when he and his childhood friend, Stephen Katz, set out to hike the AT in 1998. Bryson writes that he hoped the trail would get him fit after years of "waddlesome sloth," and although he was only in his mid-40s, he claims to have "a body that's much older." He describes his friend, the doughnut-addicted Katz, as bringing to mind "Orson Welles after a very bad night." The story of this out-of-shape pair's attempted thru-hike — Bryson and Katz finished roughly half the trail — can be found in the book "A Walk in the Woods," a best-seller that inspired many a lazy American to hit the trail. The book takes a humorous look at the trail's many characters, delves into the history of the AT and makes a plea for its conservation.

5 of 10 Scott Rogers courtesy of Scott Rogers. In 2004, Scott Rogers, 35, became the first above-the-knee amputee to hike the entire Appalachian Trail. Rogers lost his left leg in 1998 when he accidentally shot himself, but he says the accident made him stronger. He now gets around with C-leg, a prosthetic leg and foot that's driven by hydraulics and controlled by microprocessors that monitor his movement to create a stable gait. He says his kids inspired him to achieve his dream of hiking the AT, and he was further motivated when he met Lane Miliken, a 9-year-old amputee who'd read about Rogers' journey. Rogers, who was known as "One Leg" on the AT, dedicated his hike to the boy. Although his journey was challenging — several times he had to resort to crutches which made him "really feel handicapped" — Rogers is proud of his accomplishment. His advice for AT hikers? "Do not be so concerned with how many miles you cover in a day. Concentrate more on the smiles."

6 of 10 Kevin Gallagher cotesebastian/iStockphoto. Want to hike the Appalachian Trail but don’t want to commit five months of your life to it? How about just five minutes? Thanks to hiker and photographer Kevin Gallagher, you can experience the trail in all its glory in just a few moments. In 2005, Gallagher spent six months making his way from Georgia to Maine, stopping every 24 hours to take photos of the journey. By the end of his six-month trek, he had 4,000 photos, and he strung them together to create a stop-motion film. The aptly named “Green Tunnel” will give you a sense of what it’s like to hike the AT and just may inspire you to lace up your hiking boots and hit the trail yourself.

7 of 10 Jacques d'Amboise Photo: Photo by Noam Galai/Getty Images for National Dance Institute Jacques d'Amboise, once a principal dancer with the New York City Ballet, is known for his choreography, but it’s his “Trail Dance” that earns him a place on our list. In 1999, at almost 65 years old, d’Amboise began hiking the Appalachian Trail to raise money for the National Dance Institute, the dance school he’d founded. The project was named Step by Step, and during his seven-month trek, d’Amboise shared his “Trail Dance,” a short jig he’d put together for the hike, to everyone he met along the way. In return, he asked that the dancers teach his moves to two other people so that his dance would continue to inspire.

8 of 10 Andrew Thompson thinair28/iStockphoto. Many men and women have attempted to be the fastest AT thru-hikers, but the record is currently held by Andrew Thompson, who completed the trail in just 47 days, 13 hours and 31 minutes in 2005. A veteran hiker, it took Thompson three attempts to beat the previous record, and he averaged more than 45 miles per day. In his successful run, he started the trail in Maine to get past the most difficult terrain first, and by the time he ran across all 14 states, he’d lost more than 35 pounds. The women’s record for fastest thru-hike is held by Jennifer Pharr Davis who completed the AT in 57 days, 8 hours and 35 minutes in 2008.

9 of 10 Justice William O. Douglas Wikimedia Commons. A self-professed outdoorsman, former Supreme Court Justice William O. Douglas hiked the entire AT, and he even has an intersecting trail, the Douglas Trail, named after him in New Jersey. Douglas’ love for the environment often carried through to his judicial reasoning, and he even served on the Sierra Club’s board of directors and wrote prolifically about his love for nature. In a 1959 issue of Life magazine he wrote, “Hiking is not the only way to relax. Painting, gardening, tennis, fiddling, these are all means to the same end. But for me hiking is the best of all."