After 53 grueling days trekking through Antarctica, American adventurer Colin O'Brady on Wednesday became the first person to cross the continent solo and unassisted.

O'Brady, 33, embarked on the journey on Nov. 3. He traveled 932 miles, finishing the last 80 miles in 33 hours. While vacationing in Thailand 10 years ago, O'Brady sustained burns on 25 percent of his body, and after recovering, he began racing in triathlons. He has since climbed the highest peaks on every continent and in every U.S. state. Last week, he told BBC News he's lost so much weight that his watch keeps falling off his wrist.

In Antarctica, O'Brady was racing against Louis Rudd, a 49-year-old father of three and a captain in the British Army. Rudd is about 70 miles away from the finish line at the Ross Ice Shelf, and is expected to make it there on Saturday. He announced in April he was going to make the trek in honor of his friend, Henry Worsely, who died from organ failure two years ago while trying to become the first person to cross Antarctica alone and without assistance. O'Brady did not reveal he was trying to set the record until October.

The explorers had to drag 375-pound sleds containing all the food and materials they needed. For drinking water, they had to boil ice and snow, and they slept with their wet clothes so their body heat could dry them. Catherine Garcia