The 4,265km Pacific Crest Trail stretches from Canada to Mexico - roughly the distance between Singapore and China.
But it didn't stop Mr Prasatt Arumugam from doing the trek from July to December last year, as he tramped through parched deserts and icy mountain passes along the US Pacific Coast, starting in Washington State near the Canadian border and ending in Campo, California, by the Mexican border.
He is the first Singaporean to conquer the trail - walking more than 40km a day for five months.
What kept the 26-year-old going was his campaign to raise funds for the Children's Cancer Foundation (CCF).
LEFT HIS JOB
The English Literature graduate from the National University of Singapore left his job as a tutor at The Learning Lab in July to undertake the social initiative he named TrekInvicta (inspired by his favourite poem, Invictus) to raise awareness and funds for CCF where he volunteers.
He saved up while working to fund the trek, and the National University of Singapore Society (NUSS) and the National Youth Council also helped pay his expenses.
Mr Prasatt had hoped to raise $26,650 - $10 for each of the 2,650 miles he walked.
He raised $47,131.
Mr Prasatt first heard about the Pacific Crest Trail when he was on a student exchange programme at Yale University in 2013.
He visited Yosemite National Park (one of the parks on the trail) and liked it.
It intrigued him that the trail covers a diverse range of terrain, including deserts, mountain passes, meadows and river crossings.
Mr Prasatt is no stranger to treks, having hiked the Annapurna Circuit in Nepal.
He said: "The altitude demands were more on that trek but the physical demands in terms of amount climbed and distance travelled on the Pacific Crest Trail far exceeded that."
Mr Prasatt flew to Seattle, in Washington State, and started at Hart's Pass on July 16, finishing his trek at Campo near on Dec 9.
He prepared for the trek by climbing flights of stairs at places such as Pinnacle@Duxton, Mount Faber and Bukit Timah.
He did this for at least two hours every day, with trekking poles in hand and a loaded backpack.
Even after all that, the Pacific Crest Trail proved tough.
"Exhaustion, running low on food and water, and coping with the high altitude and extreme weather conditions, you name it," he said.
Mr Prasatt, who slept in his tent or in motels, told tabla! that his meals consisted of Pop-Tarts (a pre-baked pastry with sugary fillings) for breakfast, and 10 to 12 energy bars that he ate throughout the day.
At night, he would have a more substantial dinner - ramen, mashed potatoes or instant rice with tuna. He would carry a few days worth of food with him, bought from shops in towns he passed along the way.
One incident, when he was in the town of Chester in North California stocking up on his food supplies and taking shelter from a storm, touched him.
Said Mr Prasatt: "I had already been delayed by bad weather and was anxious to move on.
"There was no transport and the place I had to get to was not on a well-travelled route.
"I tried asking everywhere to see if anyone knew how I could leave town - my motel, stores and such - but to no avail."
By this point, he was getting desperate as he did not want to spend more days off the trail.
"I remembered that the local bank has a visitor's centre and told the staff I was trying to find my way out of town before the storm hit."
Many of the staff stopped what they were doing and made calls to people they knew who could help.
"Eventually, one of them - Ms Amy Jarrad - found someone willing to go out of her way to give me a ride. Amy asked me more about from where I was and why I was hiking, and she was moved by the story."
She later found him on Facebook and sent him a message of encouragement and promised to donate.
"The help came at a low point in my hike - a point where I was uncertain if I could complete the trail.
"As I walked out of the bank, I was suddenly overwhelmed by the kindness I had received and broke down - not sadness, but tears of joy.
"Till then I had been cursing my luck, but perhaps if things hadn't been as hard as they had been, I would not have had the chance to meet such beautiful souls," he said.
When Mr Prasatt was in the second month of his trek, he often got dizzy and light-headed.
He visited a clinic in Ashland, Oregon, where doctors found that he had a heart murmur.
"They said I should stop hiking, but I felt I couldn't stop, not after coming all the way.
"Instead, I took potassium supplements and carried on," said Mr Prasatt, admitting that he felt scared as worst-case scenarios flashed through his mind.
But his determination saw him through and he completed the trek.
Mr Prasatt will be receiving a medal from the Pacific Crest Trail Association for finishing the trek.
Mr Prasatt, who has started a full-time job as an English literature teacher at a secondary school, said: "The Pacific Crest Trail was an immense challenge that saw me hike through rough terrain and harsh weather for five months.
"The journey of children fighting cancer is far longer and harder. If I, as a healthy individual, could not have overcome the challenges I faced alone, what more these children?"
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