* 23.23 million - number of steps Hayden Wilson took in hiking 11,000 miles, assuming a standard 2.5-foot stride.
* 14,270 feet - height of Grays Peak, the highest point on the Continental Divide Trail.
* 8,000 miles - distance Wilson has hiked since he decided to stop carrying a stove in order to save weight.
* 6,643 feet - highest point on the Appalachian Trail at Clingmans Dome, Tenn.
* 149 days - how long it took Wilson to hike the Pacific Crest Trail in 2004 (17.9 miles a day, average).
* 128 - number of hikers who have reported completing two thru-hikes of the Appalachian Trail, according to the Appalachian Trail Conservancy.
* 35.5 miles - longest distance between water sources on the Pacific Crest Trail.
* 25 percent - approximate number of hikers who set out to thru-hike the Appalachian Trail and complete it.
* 11-13 pounds - average weight of supplies Wilson carries, not including food and water.
The Appalachian Trail
* Southern terminus: Springer Mountain, Ga.
* Northern terminus: Mount Katahdin, Maine.
* Length: 2,181 miles.
* States: Georgia, North Carolina, Tennessee, Virginia, West Virginia, Maryland, Pennsylvania, New Jersey, New York, Connecticut, Massachusetts, Vermont, New Hampshire and Maine.
*Completed: 2002 and 2006.
The Pacific Crest Trail
*Southern terminus: Campo, Calif.
*Northern terminus: Manning Park, British Columbia.
* Length: 2,663 miles.
* States: California, Oregon and California.
* Completed: 2004.
The Continental Divide Trail
* Southern terminus: Antelope Wells, N.M.
* Northern terminus: Glacier National Park, Mont.
*Length: about 3,100 miles.
* States: New Mexico, Colorado, Wyoming and Montana.
* Year Wilson completed it: 2011.
Ferdinand Magellan. Marco Polo. Lewis and Clark. Sir Francis Drake.
For all their celebrated status, the explorers who undertook history's great journeys were ultimately just people going from one place to another. The sheer simplicity of that concept, however romanticized, was what drove Hayden Wilson, 66, to put his boots on the Appalachian Trail in 2002.
"It's the satisfaction of putting your belongings on your back and starting out on a journey, not just a trip or a walk across the road but a journey that starts at one part of the country and takes you all the way to an entirely different part," Wilson said. "Every morning, you get up and know what you're doing and where you're going.
"We've all got so many complications in our lives, but on the trail there are so few complications."
In 2002, Wilson, then 57, was newly retired from the Sequatchie County school system and had no prior long-distance hiking experience. Despite near crippling pain he suffered from shin splints, he completed his marathon, "thru-hike" of the Appalachian Trail in 149 days, covering a distance of almost 2,200 miles.
Wilson was in love with life on the trail long before he climbed to the top of Mount Katahdin in Maine, but it took more than a year to sink in. Like many marathon hikers who reach the end of their first journey, he was convinced he'd had enough and swore off hiking in 2003.
The itch soon came back.
"When it started nagging me was that fall and that next winter," he said. "I started thinking, 'I've got to hike again.' It just starts sneaking up on you."
In 2004, Wilson decided to tackle the even longer Pacific Crest Trail, which runs about 2,700 miles along the West Coast from the Mexican border north to British Columbia.
Beginning in the hot, dusty shrubland near the Californian border with Mexico, the Pacific Crest Trail snakes its way up frozen, high-altitude passes, along rivers and lakes and through rain forests. For about 150 days, Wilson hiked through a range of weather conditions, from brutal heat to freezing sleet, in some of the most remote wilderness areas in the United States.
After crossing the Canadian border to finish the Pacific Crest, Wilson decided in 2005 to undertake an even greater challenge by hiking the Continental Divide Trail, which runs along the geographic backbone of America between New Mexico and Montana. At 3,100 miles, it is the second longest official scenic trail in the country after the 4,600-mile North Country Trail.
Instead of attempting another thru-hike, Wilson opted to undertake the Continental Divide in sections, beginning with an 800-mile leg in Montana. He finished his final section in New Mexico in June.
By completing three of the country's longest scenic hiking trails, Wilson qualifies for the Triple Crown, an award offered by the American Long Distance Hiking Association West to those who hike the Pacific Crest, Continental Divide and Appalachian trails. He will receive his award at a Sept. 1 gathering in Lake Wenatchee, Wash.
Whereas many marathon hikers who complete America's longest trails turn to Australia or Europe for their next challenge, Wilson said he loves domestic trails too much to look elsewhere.
He completed a second thru-hike of the Appalachian Trail in 2006. This spring, he walked a 400-mile section of the trail he said he hopes will prove the foundation of a third hike.
In 2009, a knee injury forced Wilson to abort a second thru-hiking attempt of the Pacific Crest after 1,055 miles, but he said he hopes to complete that hike in 2012.
"If I I'm still functioning. I'd like to finish it," he said. "I feel badly that it is incomplete."
Wilson, who was raised in Pikeville, Tenn., said he's grateful for the opportunities he's had to trek through parts of the country most never have the opportunity to see.
"There's an appeal to traveling through an area that so few people get to travel through," he said. "Most people who complete the trails ... tell you it changed their life and was the most satisfying experience they've ever had.
"I feel it every time I finish one of these trails, and I always wonder if I can do another one."
Despite religiously exercising for six hours a week, Wilson said he recognizes that at his age he's fighting the clock to get in the journeys he hopes to undertake.
Wilson said his passion has always been for the journey, never the destination, however, and having reached his goals once, it won't matter if he never finishes another one.
"The time will come when I can't hike any of these trails," he said. "At 66, it can't be too far away. When it happens, it will happen.
"I've done more than I ever dreamed I would do, as far as hiking. ... I wouldn't have dreamed of doing any of these things."