OREGON, United States－An Oregon man became the first person to cross Antarctica alone without any assistance on Wednesday, trekking across the polar continent in an epic 54-day journey that was previously deemed impossible.

Colin O'Brady, of Portland, finished the bone-chilling, 1,500-kilometer journey as friends, family and fans tracked the endurance athlete's progress in real time online.

"I did it!" a tearful O'Brady said on a call to his family gathered in Portland for the holidays, according to his wife, Jenna Besaw.

"It was an emotional call," she said. "He seemed overwhelmed by love and gratitude, and he really wanted to say 'Thank you' to all of us."

O'Brady was sleeping near the finish line in Antarctica late on Wednesday and could not immediately be reached for comment.

The 33-year-old O'Brady documented his nearly entirely uphill journey which he called "The Impossible First" on his Instagram page. He wrote on Wednesday that he covered the last roughly 129 kilometers in one big, impromptu final push to the finish line that took well over an entire day.

"While the last 32 hours were some of the most challenging hours of my life, they have quite honestly been some of the best moments I have ever experienced," O'Brady posted.

The day before, he posted that he was "in the zone" and thought he could make it to the end in one go.

"I'm listening to my body and taking care of the details to keep myself safe," he wrote. "I called home and talked to my mom, sister and wife I promised them I will stop when I need to."

Though others have traversed Antarctica, they either had assistance with reinforced supplies or kites that helped propel them forward.

"There were several times I considered stopping, putting my tent back up and calling it a day," he wrote in an Instagram post on Nov 18. "I wanted so badly to quit today as I was feeling exhausted and alone, but remembering all of the positivity that so many people have been sending, I took a deep breath and focused on maintaining forward progress one step at a time and managed to finish a full day."

On Day 37, or Dec 9, O'Brady wrote about how much he's changed, along with a selfie in which he looks almost in pain, snow gathered around his furry hat.

"I'm no longer the same person I was when I left on the journey, can you see it in my face?" he wrote. "I've suffered, been deathly afraid, cold and alone. I've laughed and danced, cried tears of joy and been awe-struck with love and inspiration."

AP