American explorer Colin O’Brady on Wednesday became the first person to trek across Antarctica unaided and alone, The New York Times reported. The 33-year-old covered the final 15 km of the 1,482-km journey from the so-called Messner Start on the Ronne Ice Shelf to the Ross Ice Shelf at the foot of Leverett Glacier in one final sleepless, 32-hour burst.

“I did it!” a tearful O’Brady said on a call to his family in Portland, his wife Jenna Besaw told AP. “It was an emotional call,” she added. “He seemed overwhelmed by love and gratitude, and he really wanted to say ‘thank you’ to all of us.” O’Brady could not be reached for comment.

O’Brady documented his journey, which was almost entirely uphill and called The Impossible First, on his Instagram account. On Wednesday, he wrote that he covered the last 129 km in one big “Antarctica Ultramarathon” push to the finish line that took more than a 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. “I was locked in a deep flow state the entire time, equally focused on the end goal, while allowing my mind to recount the profound lessons of this journey. I’m delirious writing this as I haven’t slept yet.”

O’Brady was in a race with Englishman Louis Rudd, 49, a close friend of British Special Forces veteran Henry Worsley, who died in 2016 while making the same attempt. Worsley had come within 126 miles of the finish. Rudd was on the ice as of Wednesday. Rudd and O’Brady left Punta Arenas in Chile on Halloween and the Antarctic Logistics & Expeditions base camp at Union Glacier on November 3. Rudd was ahead for the first week but O’Brady caught him on November 9 and soon took a lead. He had an advantage of a day or two for several weeks before the Christmas Day push.

Here are a few photographs O’Brady posted during his trek:

Colin O’Brady after finishing the nearly two-month trek. The wooden post in the background of this picture marks the edge of the Ross Ice Shelf, where Antarctica’s land mass ends and the sea ice begins.
A photo posted by the American adventurer on Day 49 of his journey.
O'Brady battled mental and physical exhaustion apart from sub-zero temperatures for close to two months to achieve the feat. He beat his nearest rival, Englishman Louis Rudd, to the finishing line.
A photo clicked on Day 24 of the trek.
O'Brady throws a pot of boiling water into the air after dinner on Day 8. The water instantly turned to ice. "That also gives you a sense of what the wind felt like on my body all day," he wrote.