10 . A Portland, Oregon man has become the first person to travel across Antarctica by himself without receiving any assistance.

Colin O’Brady has completed the 1,500-kilometer trip. He crossed the continent in 54 days. Friends, family and other people followed his progress through messages and pictures he left on social media.

O’Brady spoke with his wife Jenna Besaw by telephone soon after he completed the journey. “It was an emotional call,” she said. “He seemed overwhelmed by love and appreciation, and he really wanted to say ‘thank you’ to all of us.”

The 33-year-old O’Brady documented the trip on the social networking services Instagram. He called his journey “The Impossible First”. He wrote that he traveled the last 129 kilometers in one big, final push to the finish line. The distance took over one day to complete. O’Brady wrote, “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.”

The day before, he wrote that he was “in the zone” and thought he could make it to the end without stopping. “I was 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 would stop when I need to.”

Other people have traveled across Antarctica, but they all had some form of assistance. They either had better, more plentiful supplies or devices that helped move them forward.

In 2016, British explorer Henry Worsley died in his attempt to travel alone across Antarctica unassisted. Worsley’s friend Louis Rudd, also from Britain, is attempting an unaided solo journey in Worsley’s honor. He was competing against O’Brady to be the first to do it. Besaw told the Associated Press that her husband plans to stay in Antarctica until Rudd finishes his trip.