In May 2015, Holly Harrison — known as “Cargo” to most of his buddies — was hiking along the Appalachian Trail and taking stock of his situation. “You know, trying to figure out what I was going to do with the rest of my life,” he said.

He was 55 and had always dreamed big. He wanted to do something no one had ever done, maybe something no one would ever be able to match. But he felt time was running out.

“I just had this thought: I wonder if anybody’s ever hiked the entire Western Hemisphere,” he said, “from the bottom of South America to the top in North America.” He discover that one man had, in fact. The British explorer George Meegan did it four decades earlier, taking six years and 236 days to walk from Patagonia to the Arctic Ocean north of Alaska. Harrison thought just maybe he could do it faster.

Seven months later, he set out on his journey, making it about 1,700 miles before tearing a tendon in his left foot. He flew home and, for the next nine months, stewed, thinking about his mistakes and plotting his corrections.

What followed was a 14,481-mile journey along the Pan-American Highway with twists and turns that Harrison never could’ve anticipated: dog attacks in South America, a life-threatening heart attack in Nevada (he recovered) and a bear attack in Alaska (the bear retreated). He passed through 14 countries and used crutches for added support over the last 2,000 miles, pushing through physical pain and emotional turmoil. It became a journey of self-discovery, too.

Harrison was an Army Ranger in the early 1980s, later worked as a program manager for the Girl Scouts and spent years as a camp director. When he was 15, he hitchhiked across Nebraska. He hiked the Appalachian Trail in 2011 and had also trekked through Yellowstone and Yosemite, seeing much of the country’s natural beauty up close and personal.

At times, Harrison carried four or five days’ worth of food and water. Large drainage pipes beneath roads became a preferred overnight dwelling. “I would rate them, like a one-star to a five-star.”

He’d do as few as 5 miles and as many as 51 miles each day. But with few exceptions, Harrison woke up every day and kept moving forward.

“I didn’t have a day where I ever questioned what I was doing out there,” he said, “because I knew what the consequence was of quitting and I knew that I would just be miserable.”

He ate bread, cheese, bologna, hot dogs, canned tuna. As the weeks and months passed, so did the terrain: deserts, mountains, rain forests, jungles, swamps, rivers.

One December day, he awoke with a sharp pain in his arm. The next day the pain was much more pronounced, and Harrison knew he was having a heart attack. He was taken by a medevac helicopter to Reno and immediately went into surgery. Doctors put a stent in his heart. After four days in the hospital, he went for a walk — for 5 miles. The next day he made it 11, and then 17 the day after that. The doctors wouldn’t give him a green light to continue his journey, but he wasn’t waiting for one.

While he covered the first 11,000 miles solo, Harrison’s brother-in-law joined him in Nevada with a van to provide road support, and he hit the road again.

On May 31, Harrison set out for his last day of hiking. He had walked 14,481 miles in 530 days — an average of more than 27 miles a day. He bettered Meegan’s mark by more than five years.

“It doesn’t even seem like a finish line, you know?” he said at the end. “Look at it. I could keep walking. It’s ice.”