Monday was not an ideal morning to ski in Antarctica. The wind was fast, and a snowstorm was producing whiteout conditions, making the skiing feel like “being inside a Ping-Pong ball,” in the words of the American adventure athlete Colin O’Brady.

But there was no time to waste in a race to become the first person to cross Antarctica alone from shore to shore without any aid or support. So when O’Brady and Louis Rudd, a captain in the British Army, unzipped their tents and saw the misery they would experience on the 23rd day of their journey, they confronted it as if it were any other day. They would consume warm fluids and high-calorie snacks, and push through the unmatched exhaustion that comes from hauling a 300-pound Norwegian sled, known as a pulk, for 10 to 12 hours.

[What does it mean to cross Antarctica alone and unsupported? Here are 7 takeaways from this historic journey.]

Each day these two competitors, who have been traveling miles apart from each other and have not communicated with each other, have emerged amid an icy desert to battle the elements and one another. They’ve felt pain and frustration, taken risks and shed tears.